wrapped keystone_wait_for_propagation() with @retry_on_exception()
https://github.com/juju/charm-helpers/commit/edd813b734f230658ed9c06b8be86316ed8bbb45
wrapped keystone_ wait_for_ propagation( ) with @retry_ on_exception( )
https:/ /github. com/juju/ charm-helpers/ commit/ edd813b734f2306 58ed9c06b8be863 16ed8bbb45