When configuring temp urls, give Swift time to start up
When configuring temp urls, give Swift time to start up

Otherwise, we've seen intermittent "Unable to establish connection"
failures, with the main devstack log reporting things like

   2017-07-19 13:54:29.973 -> start proxy service
   2017-07-19 13:54:30.082 -> start OSC to store temp url key
   2017-07-19 13:54:31.908 -> OSC reports failure

Meanwhile, the s-proxy screen session tells us things like

   Jul 19 13:54:31.919988 -> start child worker
   Jul 19 13:54:32.206598 -> still loading the WSGI app

... and ports aren't actually bound until *after* the app is loaded.

Add a wait_for_service call to wait for the proxy to come up.

Change-Id: I1a722de31b144797230991700e110353a2d937dd

noironetworks/devstack,dtroyer/devstack,group-policy/devstack,nawawi/openstack,noironetworks/devstack,group-policy/devstack,openstack-dev/devstack,openstack-dev/devstack,dtroyer/devstack,nawawi/openstack