Add vpn port to firewall

src/freedombone-utils-firewall

     iptables -t nat -D POSTROUTING -s ${EXTERNAL_IPV4_ADDRESS}/24 -o ${FIREWALL_EIFACE} -j MASQUERADE
     iptables -D OUTPUT -o tun+ -j ACCEPT
     save_firewall_settings
+    sed -i '/VPN=/d' $FIREWALL_CONFIG
 }
 
 function firewall_enable_vpn {
     save_firewall_settings
 
     firewall_update_external_ip
+    echo "VPN=1194" >> $FIREWALL_CONFIG
 }
 
 function configure_firewall {