Use common "waiters.wait_for_snapshot_status" function everywhere

In Tempest we have the waiters.wait_for_snapshot_status function that
is already used in some places. So this commit replaces the use of the
wait_for_snapshot_status method defined in the base_snapshots_client.py
file with the use of the waiters.wait_for_snapshot_status function.

Change-Id: Ic017d468cc1478d8207ba482f161ed63c9b168fe
diff --git a/tempest/scenario/test_stamp_pattern.py b/tempest/scenario/test_stamp_pattern.py
index 16352c6..e7223c7 100644
--- a/tempest/scenario/test_stamp_pattern.py
+++ b/tempest/scenario/test_stamp_pattern.py
@@ -68,15 +68,15 @@
             self.snapshots_client.delete_snapshot(snapshot['id'])
             try:
                 while self.snapshots_client.show_snapshot(
-                    snapshot['id'])['snapshot']:
+                        snapshot['id'])['snapshot']:
                     time.sleep(1)
             except lib_exc.NotFound:
                 pass
         self.addCleanup(cleaner)
         waiters.wait_for_volume_status(self.volumes_client,
                                        volume['id'], 'available')
-        self.snapshots_client.wait_for_snapshot_status(snapshot['id'],
-                                                       'available')
+        waiters.wait_for_snapshot_status(self.snapshots_client,
+                                         snapshot['id'], 'available')
         self.assertEqual(snapshot_name, snapshot['display_name'])
         return snapshot