Helper to read a named config file.
    The grossness with the global is a workaround for this python bug:
    https://bugs.python.org/issue21591
    The bug prevents us from defining either a local function or a lambda
    in the scope of read_fbcode_builder_config below.

def _inner_read_config(path):
    '''
    Helper to read a named config file.
    The grossness with the global is a workaround for this python bug:
    https://bugs.python.org/issue21591
    The bug prevents us from defining either a local function or a lambda
    in the scope of read_fbcode_builder_config below.
    '''
    global _project_dir
    full_path = os.path.join(_project_dir, path)
    return read_fbcode_builder_config(full_path)