db: Retrieve VirtualInterface objects by UUID, not address

[Minghong Hou]

1. I use the method get_by_uuid from VirtualInterface to get the vif of an instance.
    vif = objects.VirtualInterface.get_by_uuid(context, port_uuid)
2. I change the 'tag' value in the vif.
3. I use the method vif.save()

Result:
I expect the the tag of my vif would be changed, but actually the LOG information of nova-compute says that 'Nonetype' object has no attribute to 'update'. By pdb check, I find out that the the method in nova/db/sqlalchemy/api/virtual_interface_update can't find the corresponding record of the instance.

The reason I guess is that when we use the method get_by_uuid, the address would be the mac address, but the address shows in the table of VirtualInterface is 'address/uuid', which causes the virtual_interface_update can't find the corresponding address.

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/nova/+/828819