Comment 1 for bug 1477484

Actually same pattern in a few other places as well:

$ grep -R "create_periodic_tasks" ./* | grep -v pyc | grep -v bak
./engine/test_stack_create.py: self.man.create_periodic_tasks()
./engine/test_stack_snapshot.py: self.engine.create_periodic_tasks()
./engine/test_stack_events.py: self.eng.create_periodic_tasks()
./engine/test_stack_delete.py: self.man.create_periodic_tasks()
./engine/test_stack_action.py: self.man.create_periodic_tasks()
./test_engine_service.py: self.eng.create_periodic_tasks()
./test_metadata_refresh.py: self.man.create_periodic_tasks()