Workaround for Netplan

- Newer Ubuntu versions use netplan instead of ifupdown by default for
  network configuration
- Scripts in /etc/network/if-pre-up.d/ does not work under netplan
- Add workaround in /etc/rc.local for the above

vpnsetup.sh

@@ -435,6 +435,7 @@ cat >> /etc/rc.local <<'EOF'
 (sleep 15
 service ipsec restart
 service xl2tpd restart
+[ -f "/usr/sbin/netplan" ] && iptables-restore < /etc/iptables.rules
 echo 1 > /proc/sys/net/ipv4/ip_forward)&
 exit 0
 EOF