Previously, the openstack::glance class would not allow users to specify an IP address to bind Glance service to. This change implements the bind_host parameter to allow users to specify an IP address for binding Glance API and Registry. Defaults to '0.0.0.0' for backwards compatibility and to bind Glance services to all addresses. Change-Id: I1e69df9401b2358b6af531c083850258c3585e41