Update to handle 10.11 and 10.12 with SIP

[drbenru]

Apple introduced a new preference file that allows to disable Bonjour advertisement in macOS with SIP. I added changes to handle this on 10.11 and 10.12.
I have only tested on 10.12.2. It detects Multicast disabled or disables it successfully. It still requires a reboot for changes to take effect.

[jonschwenn]

Hi,

Thanks for the contribution. It's glad to hear that Apple has made it a bit easier to disable bonjour advertisements. Frankly, MMV stopped routing bonjour chatter back when Apple changed between mDNSResponder and discoveryd multiple times during the 10.10 lifecycle. It simply wasn't attainable to keep updating this many Macs that were not managed by us directly.

I have no problem merging it, but I'd recommend to keep the logic checks inside the main if statement. It's a bit messy as is, but the idea is that there would be one master logic check to make sure the bash script wasn't running on Linux or something. Maybe there is a cleaner way to setup the various logic checks for the different methods to disabling bonjour advertising for OS versions that nearly span the last decade. Thanks 😃