Comment 5 for bug 1383973

The key reason is that currently glance can receives new image location and save it to database only after its bits saving logic return (affect by glance and glance_store logics). So before upload execution 'thread' finish, glance doesn't know any location information of that 'saving' image, so delete 'thread' just think theres' no any locations/bits of the image need to remove. Figuring out solution.