Adapt to cleanup images as well

.gitlab-ci.yml

@@ -28,8 +28,8 @@ docker:
         - master
         - schedules
 
-# VM cleanup for old failed tests to avoid filling our Openstack quota
-vm_cleanup:
+# VM and image cleanup for old failed tests
+testing_cleanup:
     stage: cleanup
     image:
         name: gitlab-registry.cern.ch/linuxsupport/openstack-testing-cleanup:latest