Reassign MAC address for vm  when resize_revert

In the case of a resize or migrate on the same host, we need to assign
a temp mac address to the source LPAR so we don't have a conflict when
another LPAR is booted with the same mac address as the original LPAR.
We need reassign the original mac address, replacing the temp mac on
the old instance during revert resize. The new instance has been
destroyed before this method, so remove the precondition to make sure
original mac address be set.

Fixes bug #1196404

Change-Id: I709292a7725f0a21f04f1c3c79f2fafc4437e402
Merge "Reassign MAC address for vm  when resize_revert"