Really normalize the path by adding a missing leading slash.

def normpath(path, keep_trailing=False):
    """Really normalize the path by adding a missing leading slash."""
    new_path = k_paths.normpath(path)
    if keep_trailing and path.endswith("/") and not new_path.endswith("/"):
        new_path = new_path + "/"
    if not new_path.startswith('/'):
        return '/' + new_path
    return new_path