def create_done_path(done_path, uid=-1, gid=-1):
    with file(done_path, 'w'):
        pass
    os.chown(done_path, uid, gid);
create a done file to avoid re-doing the mon deployment
dataset/ETHPy150Open ceph/ceph-deploy/ceph_deploy/hosts/remotes.py/create_done_path