The current production docker verison or configuration only allows to
forward a port either by using udp or tcp, not both (even though that's
what is suggested by fluentd).
docker will use the last entry and silently delete the former.

This is not a problem for us since we only talk to fluentd via tcp.

This would only be a problem if fluentd wasn't running, but
since fluentd doesn't log to fluentd, kibana wouldn't help anyway.