Nflog v4

I fixed the error discussed on IRC:

"ntv->livedev = LiveGetDevice(&nflconfig->numgroup);
LiveGetDevice expects a string, numgroup is a single char"

I made the following tests:

iptables -A INPUT -j NFLOG --nflog-group 2
/usr/bin/suricata -c /etc/suricata/suricata.yaml --nflog --runmode=single
ping -c 3192.168.178.130
/usr/bin/suricata -c /etc/suricata/suricata.yaml --nflog
ping -c 3 192.168.178.130

Last PR: https://github.com/inliniac/suricata/pull/863