Verified with ovirt-engine-3.6.0-0.0.master.20150519172219.git9a2e2b3.el6.noarch.
If I understand correctly from the patch, the addVmCommand canDoAction function will now deny adding a vm to an uninitialized dc as described in this bz with the error 'ACTION_TYPE_FAILED_IMAGE_REPOSITORY_NOT_FOUND'.
This is the behaviour I'm getting when:
1. adding new dc.
2. adding new cluster.
3. dc is uninitialized.
4. add vm with to new cluster.
<fault>
<reason>Operation Failed</reason>
<detail>
[Cannot add VM: Storage Domain cannot be accessed. -Please check that at least one Host is operational and Data Center state is up.]
</detail>
</fault>