V2V : Problem removing snapshots from VM's imported using virt-v2v

I've hit a problem with virt-v2v which is causing me some issues.
When Importing a virt-v2v VM from the Export SD, it creates a zero field entry in the database.
Field "vm_snapshot_id" in table "images" is created with entry "00000000-0000-0000-0000-000000000000". 
This causes problems if you later create and then attempt to remove a snapshot.

Removal of the snapshot reports error :-

Operation Canceled (sic)

- Cannot Merge Snapshot. VM's image does not exist
- Cannot Merge Snapshot. Removing the VM's active snapshot is not allowed.

This appears to be because this field should not contain duplicate entries.  

As reported in support case 00769525. Current solution is to set a random id for zero entry "vm_shapshot_id" in the images table.