Updated openstack/openstack
Project: openstack/nova  d1f8c47d2477bbce40492ed293cee7091ff50ae2

object-ify API v2 availability_zone extension

This change converts the availability_zone extension to use the
Service object instead of direct database access.

Related to blueprint compute-manager-objects-juno

Change-Id: If5baafd8ec85be1ea1cd6580ae10ef3d51366c9c