Do not block create and destroy volume if api version is 3.1 or later.

fixes #2229 add an IAM role field to a compute image.

This allows use of IAM to control access to AWS services within an instance.

fixes #1944 - Listing VMWare virtual machines under Computer resources is slow.

fixes #2061 - test if oVirt API has HTTPS redirect

rest_client will refuse to follow redirects on POST requests, so the URL must
be entered as HTTPS. Don't require HTTPS as dev environments may be HTTP-only.

fixes #1886 adds Rackspace V2 support

Based on GregSutcliffe's initial pull request.

fixes #1899 require HTTPS URL for oVirt API, now HTTPS-only

fixes #1637 adds spice support

added vm name and cursor release instruction to the spice console title.
this is a follow up to 057d497

fixes #1589 provisioning vmware support

if the ovirt host uses spice now you can connect

add compute_resource.supports_update? to current provider set