Renamed TP Plugs in HomeKit app are reset to default 'TP Plug' after Homebridge restart
<!-- Provide a general summary in the Title above -->

### Expected Behavior
Renamed plugs in homekit should persists across restarts of the Homebridge service.


### Current Behavior
Plug name is reset to 'TP Plug' after Homebridge service restart
Also the plug drops out of any automation in the HomeKit app

### Steps to Reproduce (for bugs)
I don't believe this is a bug necessary - I did see some comments about limited support of naming devices from within Homebridge, but I don't see a way to name specific devices with this plugin anyway (am I missing something?)

### Versions
<!-- Please run commands and include versions below. -->
- **Node**:  v10.16.0
- **Homebridge**: 0.4.50
- **OS**:   Linux docker 4.4.0-148-generic #174-Ubuntu SMP Tue May 7 12:20:14 UTC 2019 x86_64 GNU/Linux



### Configuration
<!-- Please include the TplinkSmarthome platform section of your config.json file.
Paste between the the two ``` lines below.
-->
```
None - it was auto discovered and did not add any config

```

### Homebridge Log / Command Output
<!-- Paste relevant output between the two ``` lines below
  - Remove any sensitive information, passwords, etc.
  - If output is long:
    - Please extract only the relevant portions if possible (remove other plugin's output, etc)
    - Consider creating a gist, etc
  - However, please include the beginning of the log where the homebridge initialization happens if possible
-->
```
[8/4/2019, 8:14:49 PM] [homebridge-tplink-smarthome.TplinkSmarthome] homebridge-tplink-smarthome v4.0.1, node v10.16.0, homebridge v0.4.50
[8/4/2019, 8:14:49 PM] [homebridge-tplink-smarthome.TplinkSmarthome] Configuring cached accessory: [TP-LINK_Smart Plug_2E48] undefined 479ed827-fdd3-42fb-b7c5-5475b043defd

.....


[8/4/2019, 8:14:49 PM] [homebridge-tplink-smarthome.TplinkSmarthome] New Device Online: [TP Plug] plug [8006CDA404CF0069BDBBB3BD90D6532F1AEE0DCB] 10.0.1.6 9999
[8/4/2019, 8:14:49 PM] [homebridge-tplink-smarthome.TplinkSmarthome] Adding: [TP Plug] plug [8006CDA404CF0069BDBBB3BD90D6532F1AEE0DCB]
HAP Warning: Characteristic 00000053-0000-1000-8000-0026BB765291 not in required or optional characteristics for service 0000003E-0000-1000-8000-0026BB765291. Adding anyway.


```


from what I can see those are the only relevant logs.


thanks
