HAP warning Fan characteristics
Getting the following after setting up a fan accessory:

```
May 10 00:03:46 raspberrypi homebridge[31961]: HAP Warning: Characteristic 00000025-0000-1000-8000-0026BB765291 not in required or optional characteristics for service 000000B7-0000-1000-8000-0026BB765291. Adding anyway.
May 10 00:03:46 raspberrypi homebridge[31961]: [2018-5-10 00:03:46] [Broadlink RM] Lüftung Accessory Ready
May 10 00:03:46 raspberrypi homebridge[31961]: [2018-5-10 00:03:46] [Broadlink RM] Klimaanlage Accessory Ready
May 10 00:03:46 raspberrypi homebridge[31961]: /usr/local/lib/node_modules/homebridge-broadlink-rm/node_modules/chai/lib/chai/assertion.js:141
May 10 00:03:46 raspberrypi homebridge[31961]:       throw new AssertionError(msg, {
May 10 00:03:46 raspberrypi homebridge[31961]:       ^
May 10 00:03:46 raspberrypi systemd[1]: homebridge.service: Main process exited, code=exited, status=1/FAILURE
May 10 00:03:46 raspberrypi systemd[1]: homebridge.service: Unit entered failed state.
May 10 00:03:46 raspberrypi systemd[1]: homebridge.service: Failed with result 'exit-code'.
```
