announcing wrong address on mdns

[relet]

Running labrador on a machine with multiple interfaces will make it announce wrong addresses on mdns.

On lab2, the last interface (completely unrelated) is

6: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:b6:fb:97:36 brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0
       valid_lft forever preferred_lft forever
    inet6 fe80::42:b6ff:fefb:9736/64 scope link 
       valid_lft forever preferred_lft forever

and labrador announces itself with inet 172.17.0.1