Ties quantum, melange, and nova network model

get_instance_nw_info() now returns network model, and keeps the network
info cache up to date.
virt shim and translation in place for virts to get at the old stuff

Change-Id: I070ea7d8564af6c644059d1c209542d250d19ddb

nova/api/openstack/compute/ips.py

@@ -93,7 +93,6 @@ class Controller(wsgi.Controller):
         context = req.environ["nova.context"]
         instance = self._get_instance(context, server_id)
         networks = common.get_networks_for_instance(context, instance)
-
         if id not in networks:
             msg = _("Instance is not a member of specified network")
             raise exc.HTTPNotFound(explanation=msg)