Well, it seems that the ovirt.VMManager.destroy has no argument named gracefully and free_mac_addresses.
So, the vm.destroy(gracefully=True, free_mac_addresses=False) may cause the (vm_type=v2v, target=ovirt) case down.

But I think we need to update the ovirt.VMManager class.
Since the gracefully and free_mac_address is used in env_process several times.

It seems the ovirt.VMManager class is outdated for a long time. Maybe we need to
take a look at the v2v submodule and @chuanchang seems too busy.