Delete given temporary directory and all its contents.

def _cleanup_temp_dir(self, base_dir):
        """Delete given temporary directory and all its contents."""
        if self._should_cleanup_temp_dir:
            logging.debug('Cleaning up temporary directory %s.', base_dir)
            if self._user is None:
                util.rmtree(base_dir, onerror=util.log_rmtree_error)
            else:
                rm = subprocess.Popen(self._build_cmdline(['rm', '-rf', '--', base_dir]),
                                      stderr=subprocess.PIPE)
                rm_output = rm.stderr.read().decode()
                rm.stderr.close()
                if rm.wait() != 0 or rm_output:
                    logging.warning("Failed to clean up temp directory %s: %s.",
                                    base_dir, rm_output)
        else:
            logging.info("Skipping cleanup of temporary directory %s.", base_dir)