Use common "waiters.wait_for_image_status" function everywhere

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

Change-Id: If42cfbfa1f7dae5af276e80f38f6294ced00ac5b
diff --git a/tempest/api/volume/test_volumes_actions.py b/tempest/api/volume/test_volumes_actions.py
index e52216f..5975231 100644
--- a/tempest/api/volume/test_volumes_actions.py
+++ b/tempest/api/volume/test_volumes_actions.py
@@ -125,7 +125,7 @@
             disk_format=CONF.volume.disk_format)['os-volume_upload_image']
         image_id = body["image_id"]
         self.addCleanup(self._cleanup_image, image_id)
-        self.image_client.wait_for_image_status(image_id, 'active')
+        waiters.wait_for_image_status(self.image_client, image_id, 'active')
         waiters.wait_for_volume_status(self.client,
                                        self.volume['id'], 'available')