fix ip6tables reference error in install_iptables_setup.sh
fix ip6tables reference error in install_iptables_setup.sh

firewalla/firewalla,MelvinTo/firewalla,MelvinTo/firewalla,firewalla/firewalla,MelvinTo/firewalla,MelvinTo/firewalla,firewalla/firewalla,firewalla/firewalla,firewalla/firewalla,MelvinTo/firewalla