handle new tempest swift interface

'....container_client.list_container_contents()' has moved to
'....container_client.list_container_objects()' in version 'Queens'
and will be removed in version 'Rocky'

Change-Id: I1314f75e5ac0bb8db30abb1ad11997fa9a1bae36
diff --git a/ceilometer/tests/tempest/scenario/test_object_storage_telemetry_middleware.py b/ceilometer/tests/tempest/scenario/test_object_storage_telemetry_middleware.py
index c399a6f..be3e03a 100644
--- a/ceilometer/tests/tempest/scenario/test_object_storage_telemetry_middleware.py
+++ b/ceilometer/tests/tempest/scenario/test_object_storage_telemetry_middleware.py
@@ -122,7 +122,7 @@
         name = data_utils.rand_name('swift-scenario-container')
         self.container_client.create_container(name)
         # look for the container to assure it is created
-        self.container_client.list_container_contents(name)
+        self.container_client.list_container_objects(name)
         LOG.debug('Container %s created' % (name))
         self.addCleanup(self.container_client.delete_container,
                         name)