Close log stream and stream_lock.

def close(self):
        """
        Close log stream and stream_lock. """
        try:
            self._close()
            if hasattr(self.stream_lock, 'closed') and \
                    not self.stream_lock.closed:
                self.stream_lock.close()
        finally:
            self.stream_lock = None
            if Handler:
                Handler.close(self)