Stale multicast address

[wasnotrice]

When an interface has been changed to a different network, it can use a stale multicast address, resulting in an EADDRNOTAVAIL error.

Expected: the interface uses the multicast address for the current network
Actual: the interface uses the multicast address for the first network it saw

Steps to reproduce:

1. Connect to a wifi network
2. Start a dnssd browser
3. Stop the dnssd browser
4. Connect to a different wifi network
5. Start a dnssd browser

An error like this is thrown:

Error: setMulticastInterface EADDRNOTAVAIL
at Socket.setMulticastInterface (dgram.js:566:11)
at Socket.eval (webpack:///./node_modules/dnssd/lib/NetworkInterface.js?:238:41)
at Socket.emit (events.js:182:13)
at startListening (dgram.js:128:10)
at state.handle.lookup (dgram.js:249:7)
at process._tickCallback (internal/process/next_tick.js:63:19)