Description of problem:
After creating a VM using instancetype/preference a revision controller is created and the VM revisionName field is being added.
If the ControllerRevision is being deleted before deleting the VM (such is the case when calling "delete namespace"), the VM will be stuck and won't be deleted until
the revisionName field is removed from the VM.

Version-Release number of selected component (if applicable):
4.13

How reproducible:
100%

Steps to Reproduce:
1. Create a VM with instanceType
2. Start the VM (so the controllerRevision will be created)
3. Delete the namespace

Actual results:
The VM (and namespace) are stuck on termination phase until the instancetype.revisionName field is removed

Expected results:
The VM and namespace should be deleted

Additional info: