Refactor the port search logic
Refactor the port search logic

Trying to combine len(ports) and nat_network logic led to weird
debugging. Split the two so that we don't try to search for a network to
attach the fip to if there is only one port on the server.

Change-Id: I1bc83e34a6f66cc5a8eb7ffa66f0288919210d4d

stackforge/python-openstacksdk,openstack/python-openstacksdk,dtroyer/python-openstacksdk,openstack-infra/shade,openstack-infra/shade,stackforge/python-openstacksdk,dtroyer/python-openstacksdk,openstack/python-openstacksdk