Create ports in quantum matching hypervisor MAC addresses.

When hypervisors supply a set of MAC addresses for instances, the
network driver is responsible for matching up the requested MACs and
the available (or requested) networks.

The simplest case, which this patch addresses, is to create ports in
quantum on the desired networks, rather than having quantum create
them dynamically with dynamically created MAC addresses.

Change-Id: I84cd96671b76b8beaa31436c8a438f7818ef622f
Merge "Create ports in quantum matching hypervisor MAC addresses."