IP Masquerading fails

[jdknives]

Describe the bug
When running the VPN-server the masquerading fails, most likely because the correct interface could not be fetched correctly.

25T16:27:40+02:00" level=error msg="Error serving" error="error enabling IP masquerading for : error running command iptables -t nat -A POSTROUTING -o -j MASQUERADE: exit status 2

Environment information:

• OS: e.g. Linux

Context

Initially we thought this was related to the IP collission from skycoin/skybian#84 but it happens independently.