Close self connections.

async def cleanup(self, app):
        """Close self connections."""
        self.conn.close()
        if self.pubsub_conn:
            self.pubsub_reader.cancel()
            self.pubsub_conn.close()
        # give connections a chance to actually terminate
        # TODO: use better method once it will be added,
        # see https://github.com/jonathanslenders/asyncio-redis/issues/56
        await asyncio.sleep(0)