This makes internal changes to the xen glance plugins so that they are
internally passing information about the glance servers by urls. It
does not change the surface of the plugin (that will come later), so
at a top level we are still thinking of glance as a host, port, and
use_ssl. However that's immediately converted to an endpoint url which
is then used for all the rest of the effort.
Change-Id: Ie1dce099846c725ff1ad7bb32f74aa6ae701ee9a
Sean Dague
6ebd61b28b