Hostname does not update
**Describe Your Problem:**
When updating my Synology NAS 'Servername' and changing 'DSM_HOSTNAME' in Docker, the logs show an error with an old 'servername'

**Screenshots:**

<img width="516" alt="Schermafbeelding 2021-03-27 om 15 17 38" src="https://user-images.githubusercontent.com/75937213/112723619-d4a81a00-8f0f-11eb-985e-f3b0f57175c5.png">
<img width="399" alt="Schermafbeelding 2021-03-27 om 15 17 00" src="https://user-images.githubusercontent.com/75937213/112723624-d70a7400-8f0f-11eb-817b-291d29c908c4.png">
<img width="691" alt="Schermafbeelding 2021-03-27 om 15 16 52" src="https://user-images.githubusercontent.com/75937213/112723627-d96cce00-8f0f-11eb-8527-12a91784e0f9.png">

**Environment:**
* **Host Operating System**: Synology NAS (latest update)
* **Docker Version**: 18.09 (latest)

I have tried rebooting Docker and the image, but with no luck. Updating the image resulted in a servername 'homebridge' in the widget overview in the UI, but obviously my servername (via Server > Info in my NAS) is: 'Lafranca'.

Although my accessories work fine, any help would be appreciated.

BW,
Jeff
