Fix unit-tests for the change made to disallow deleting a project sometime
    
    Basically, we do not allow a project to be deleted when its ACLs are
    being refreshed in the backend. It seems we sometime have a small race
    condition in the tests, so here we're making sure we're testing when
    it is locked and when it is not.
    
    Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr>