Use external IP for public interfaces
Use external IP for public interfaces

If available, we should be using the external_ip for the public hostname
and public ip variables. This way, the webconsole and other APIs will be
made available through the external network rather than just using the
internal, non public, one

Change-Id: I1d17ea8f9a14736593df56d288eb0147a58bb957

dprince/tripleo-heat-templates,dprince/tripleo-heat-templates,openstack/tripleo-heat-templates,openstack/tripleo-heat-templates