When re6st attempts to use UPnP and IPv6 is enabled at the same time,
the external IPv4 was published for IPv6 protocols.
For example, machine6 in the demo had:
  10.0.1.3,1194,tcp;10.0.1.3,1194,udp;10.0.1.3,1195,udp6

This caused re6stnet to crash (socket.gaierror) if GEOIP2_MMDB is set.

With this commit, IPv4 & IPv6 are now processed independently.