I configured compute resource VMware in Foreman 1.11.2 and all (I tested) works fine except listing VMs.

In the log it generates this error.

2016-06-21T10:47:39 [app] [W] Error has occurred while listing VMs on VCenter (VMware)
 | RuntimeError: unknown VMODL type VirtualPCIPassthroughVmiopBackingInfo
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/type_loader.rb:103:in `make_type'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/type_loader.rb:65:in `block in get'
 | /usr/lib/ruby/2.1.0/monitor.rb:211:in `mon_synchronize'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/type_loader.rb:63:in `get'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/deserialization.rb:85:in `deserialize'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/deserialization.rb:123:in `block in traverse_data'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/deserialization.rb:105:in `each'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/deserialization.rb:105:in `traverse_data'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/deserialization.rb:88:in `deserialize'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/deserialization.rb:118:in `block in traverse_data'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/deserialization.rb:105:in `each'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/deserialization.rb:105:in `traverse_data'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/deserialization.rb:88:in `deserialize'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/deserialization.rb:123:in `block in traverse_data'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/deserialization.rb:105:in `each'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/deserialization.rb:105:in `traverse_data'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/deserialization.rb:88:in `deserialize'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/deserialization.rb:123:in `block in traverse_data'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/deserialization.rb:105:in `each'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/deserialization.rb:105:in `traverse_data'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/deserialization.rb:88:in `deserialize'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/deserialization.rb:118:in `block in traverse_data'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/deserialization.rb:105:in `each'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/deserialization.rb:105:in `traverse_data'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/deserialization.rb:88:in `deserialize'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/connection.rb:68:in `block in parse_response'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/connection.rb:68:in `map'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/connection.rb:68:in `parse_response'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/connection.rb:90:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/basic_types.rb:205:in `_call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/basic_types.rb:74:in `block (2 levels) in init'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/basic_types.rb:183:in `_get_property'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rbvmomi-1.8.2/lib/rbvmomi/basic_types.rb:35:in `block (2 levels) in init'
 | /usr/share/foreman/app/services/fog_extensions/vsphere/mini_servers.rb:26:in `block in allvmsbyfolder'
 | /usr/share/foreman/app/services/fog_extensions/vsphere/mini_servers.rb:22:in `each'
 | /usr/share/foreman/app/services/fog_extensions/vsphere/mini_servers.rb:22:in `allvmsbyfolder'
 | /usr/share/foreman/app/services/fog_extensions/vsphere/mini_servers.rb:24:in `block in allvmsbyfolder'
 | /usr/share/foreman/app/services/fog_extensions/vsphere/mini_servers.rb:22:in `each'
 | /usr/share/foreman/app/services/fog_extensions/vsphere/mini_servers.rb:22:in `allvmsbyfolder'
 | /usr/share/foreman/app/services/fog_extensions/vsphere/mini_servers.rb:24:in `block in allvmsbyfolder'
| /usr/share/foreman/app/services/fog_extensions/vsphere/mini_servers.rb:22:in `each'
 | /usr/share/foreman/app/services/fog_extensions/vsphere/mini_servers.rb:22:in `allvmsbyfolder'
 | /usr/share/foreman/app/services/fog_extensions/vsphere/mini_servers.rb:24:in `block in allvmsbyfolder'
 | /usr/share/foreman/app/services/fog_extensions/vsphere/mini_servers.rb:22:in `each'
 | /usr/share/foreman/app/services/fog_extensions/vsphere/mini_servers.rb:22:in `allvmsbyfolder'
 | /usr/share/foreman/app/services/fog_extensions/vsphere/mini_servers.rb:24:in `block in allvmsbyfolder'
 | /usr/share/foreman/app/services/fog_extensions/vsphere/mini_servers.rb:22:in `each'
 | /usr/share/foreman/app/services/fog_extensions/vsphere/mini_servers.rb:22:in `allvmsbyfolder'
 | /usr/share/foreman/app/services/fog_extensions/vsphere/mini_servers.rb:12:in `all'
 | /usr/share/foreman/app/controllers/compute_resources_vms_controller.rb:4:in `index'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_controller/metal/implicit_render.rb:4:in `send_action'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/abstract_controller/base.rb:189:in `process_action'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_controller/metal/rendering.rb:10:in `process_action'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/abstract_controller/callbacks.rb:20:in `block in process_action'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:113:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:113:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:552:in `block (2 levels) in compile'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:502:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:502:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:495:in `block (2 levels) in around'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:306:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:306:in `block (2 levels) in halting'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rails-observers-0.1.2/lib/rails/observers/action_controller/caching/sweeping.rb:73:in `around'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:452:in `public_send'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:452:in `block in make_lambda'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:305:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:305:in `block in halting'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:494:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:494:in `block in around'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:502:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:502:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:495:in `block (2 levels) in around'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:306:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:306:in `block (2 levels) in halting'
 | /usr/share/foreman/app/controllers/concerns/application_shared.rb:13:in `set_timezone'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:429:in `block in make_lambda'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:305:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:305:in `block in halting'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:494:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:494:in `block in around'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:502:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:502:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:495:in `block (2 levels) in around'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:306:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:306:in `block (2 levels) in halting'
 | /usr/share/foreman/app/models/concerns/foreman/thread_session.rb:32:in `clear_thread'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:429:in `block in make_lambda'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:305:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:305:in `block in halting'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:494:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:494:in `block in around'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:502:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:502:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:495:in `block (2 levels) in around'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:306:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:306:in `block (2 levels) in halting'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rails-observers-0.1.2/lib/rails/observers/action_controller/caching/sweeping.rb:73:in `around'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:452:in `public_send'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:452:in `block in make_lambda'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:305:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:305:in `block in halting'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:494:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:494:in `block in around'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:502:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:502:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:86:in `run_callbacks'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/abstract_controller/callbacks.rb:19:in `process_action'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_controller/metal/rescue.rb:29:in `process_action'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_controller/metal/instrumentation.rb:32:in `block in process_action'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/notifications.rb:159:in `block in instrument'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/notifications.rb:159:in `instrument'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_controller/metal/instrumentation.rb:30:in `process_action'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_controller/metal/params_wrapper.rb:250:in `process_action'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activerecord-4.1.14.2/lib/active_record/railties/controller_runtime.rb:18:in `process_action'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/abstract_controller/base.rb:136:in `process'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionview-4.1.14.2/lib/action_view/rendering.rb:30:in `process'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_controller/metal.rb:196:in `dispatch'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_controller/metal/rack_delegation.rb:13:in `dispatch'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_controller/metal.rb:232:in `block in action'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_dispatch/routing/route_set.rb:80:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_dispatch/routing/route_set.rb:80:in `dispatch'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_dispatch/routing/route_set.rb:48:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_dispatch/journey/router.rb:73:in `block in call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_dispatch/journey/router.rb:59:in `each'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_dispatch/journey/router.rb:59:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_dispatch/routing/route_set.rb:690:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/apipie-rails-0.3.6/lib/apipie/static_dispatcher.rb:65:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/apipie-rails-0.3.6/lib/apipie/extractor/recorder.rb:132:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/apipie-rails-0.3.6/lib/apipie/middleware/checksum_in_headers.rb:27:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rack-1.5.5/lib/rack/etag.rb:23:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rack-1.5.5/lib/rack/conditionalget.rb:25:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rack-1.5.5/lib/rack/head.rb:11:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_dispatch/middleware/params_parser.rb:27:in `call'
 | /usr/share/foreman/lib/middleware/catch_json_parse_errors.rb:9:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_dispatch/middleware/flash.rb:254:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rack-1.5.5/lib/rack/session/abstract/id.rb:225:in `context'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rack-1.5.5/lib/rack/session/abstract/id.rb:220:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_dispatch/middleware/cookies.rb:562:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activerecord-4.1.14.2/lib/active_record/query_cache.rb:36:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activerecord-4.1.14.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:621:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/callbacks.rb:82:in `run_callbacks'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_dispatch/middleware/callbacks.rb:27:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_dispatch/middleware/remote_ip.rb:76:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/railties-4.1.14.2/lib/rails/rack/logger.rb:38:in `call_app'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/railties-4.1.14.2/lib/rails/rack/logger.rb:22:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_dispatch/middleware/request_id.rb:21:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rack-1.5.5/lib/rack/methodoverride.rb:21:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rack-1.5.5/lib/rack/runtime.rb:17:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/activesupport-4.1.14.2/lib/active_support/cache/strategy/local_cache_middleware.rb:26:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/actionpack-4.1.14.2/lib/action_dispatch/middleware/static.rb:84:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rack-1.5.5/lib/rack/sendfile.rb:112:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/railties-4.1.14.2/lib/rails/engine.rb:514:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/railties-4.1.14.2/lib/rails/application.rb:144:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/railties-4.1.14.2/lib/rails/railtie.rb:194:in `public_send'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/railties-4.1.14.2/lib/rails/railtie.rb:194:in `method_missing'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rack-1.5.5/lib/rack/builder.rb:138:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rack-1.5.5/lib/rack/urlmap.rb:65:in `block in call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rack-1.5.5/lib/rack/urlmap.rb:50:in `each'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/rack-1.5.5/lib/rack/urlmap.rb:50:in `call'
 | /usr/lib/ruby/vendor_ruby/phusion_passenger/rack/thread_handler_extension.rb:74:in `process_request'
 | /usr/lib/ruby/vendor_ruby/phusion_passenger/request_handler/thread_handler.rb:141:in `accept_and_process_next_request'
 | /usr/lib/ruby/vendor_ruby/phusion_passenger/request_handler/thread_handler.rb:109:in `main_loop'
 | /usr/lib/ruby/vendor_ruby/phusion_passenger/request_handler.rb:455:in `block (3 levels) in start_threads'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/logging-2.1.0/lib/logging/diagnostic_context.rb:450:in `call'
 | /usr/share/foreman/vendor/ruby/2.1.0/gems/logging-2.1.0/lib/logging/diagnostic_context.rb:450:in `block in create_with_logging_context'

I think it is related to https://github.com/fog/fog-vsphere/issues/36 which tells rbvmomi does lack vSphere 6 support for now. Adding this support will hopefully fix Foremans capability to list the VMs of a vCenter 6 automatically.