Add cost time printing in wait_for_volume_resource_status

This is to add printing of cost time for a volume resource
to reach the specified statuses.

Change-Id: I8cf5de6a8c386a7175a4d65b729e41b05c01406d
diff --git a/tempest/common/waiters.py b/tempest/common/waiters.py
index f4c2866..10afee0 100644
--- a/tempest/common/waiters.py
+++ b/tempest/common/waiters.py
@@ -211,6 +211,8 @@
                        (resource_name, resource_id, statuses, resource_status,
                         client.build_timeout))
             raise lib_exc.TimeoutException(message)
+    LOG.info('%s %s reached %s after waiting for %f seconds',
+             resource_name, resource_id, statuses, time.time() - start)
 
 
 def wait_for_volume_retype(client, volume_id, new_volume_type):