RHV: attempting to disable "Allow Duplicates" for Mac Pools failed, and now nothing works.

Issue

• Attempting to disable "Allow Duplicates" option for the MAC Pool failed with:

Error while executing action UpdateMacPool: Internal Engine Error

• Now several operations, such as UpdateMacPoolCommand, RemoveVmInterfaceCommand, AddVmInterfaceCommand and even RemoveVmCommand are failing with:

Exception: javax.ejb.EJBTransactionRolledbackException: Pool for id="0000002f-002f-002f-002f-000000000108" does not exist

• RemoveVm also shows this:

(org.ovirt.thread.pool-6-thread-15) [97376231-9e23-4ca7-b349-e7d6dcdb7725] EVENT_ID: USER_REMOVE_VM_FINISHED_WITH_ILLEGAL_DISKS(172), Correlation ID: 97376231-9e23-4ca7-b349-e7d6dcdb7725, Job ID: 1a6c79a0-c1a3-4eaf-92fb-c09d579464da, Call Stack: null, Custom ID: null, Custom Event ID: -1, Message: VM test5 has been removed, but the following disks could not be removed: <UNKNOWN>. These disks will appear in the main disks tab in illegal state, please remove manually when possible.