Fixes #6608 - expose disk usage info through available_storage_domains API

Fixes #6816 - pass oVirt quota as nil instead of "" to prevent server error

fixes #5760 - selectable VMware virtual HW version

fixes #5197 - Preallocated disk support for oVirt

Fixes #6099 - Bubble Fog::Errors up to Host

fixes #5652 - run parse_args when calling new_vm for compute profiles

fixes #6030 - update list of VMware guest types

fixes #4590 - convert VMware SCSI controller type during creation

fixes #4612 show friendly CR names, fix typo in oVirt name

fixes #5453 - ensure all VMware compute attribute keys are symbolized