Push state to QSUSB, retry with backoff.

def _callback_set_qs_value(self, key, val, success):
        """Push state to QSUSB, retry with backoff."""
        set_url = URL_SET.format(self._url, key, val)
        with self._lock:
            for _repeat in range(1, 6):
                set_result = requests.get(set_url)
                if set_result.status_code == 200:
                    set_result = set_result.json()
                    if set_result.get('data', 'NO REPLY') != 'NO REPLY':
                        # self.devices._set_qs_value(key, set_result['data'])
                        success()
                        return True
                sleep(0.01 * _repeat)
        _LOGGER.error("Unable to set %s", set_url)
        return False