Remove data directory from arguments to pass to upgrade function.

def _clean_args(sys_argv, args):
    """Remove data directory from arguments to pass to upgrade function.
    """
    base = [x for x in sys_argv if
            x.startswith("-") or not args.datadir == os.path.abspath(os.path.expanduser(x))]
    # Remove installer only options we don't pass on
    base = [x for x in base if x not in set(["--minimize-disk"])]
    if "--nodata" in base:
        base.remove("--nodata")
    else:
        base.append("--data")
    return base