Merge pull request #1415 from johnelse/cp-5811

Add utilisation tracking to VGPU types
Add helper functions for detecting the passthrough VGPU_type

Signed-off-by: John Else <john.else@citrix.com>
Fix a pattern patch

It's only by chance that this pattern match worked as intended.

Signed-off-by: John Else <john.else@citrix.com>
CP-5842: Blank VGPU.resident_on on VM shutdown

Signed-off-by: John Else <john.else@citrix.com>