Fix deleting a project if creation failed
    
    Basically, if a project fails to be created we want to have it
    removed from the DB. So far, we only reverted and removed the
    project from the DB if the repositories were found on disk. With
    this commit, we'll remove the project from the DB for any
    exception raised.
    
    Fixes https://pagure.io/pagure/issue/4384
    
    Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr></pingou@pingoured.fr>