Make fixed_ip_get_by_address() take columns_to_join

This will let the FixedIP object make some significantly more
efficient queries by asking for network and/or instance at the
same times as the FixedIP itself.

Related to nova-network-objects

Change-Id: I7ae971469585f072cd039f30faf71a4d48c9fd04
Merge "Make fixed_ip_get_by_address() take columns_to_join"