use iptables-restore in all ikev2 firewall scenarios

testing/tests/ikev2/reauth-early/pretest.dat

@@ -1,5 +1,5 @@
-moon::/etc/init.d/iptables start 2> /dev/null
-carol::/etc/init.d/iptables start 2> /dev/null
+moon::iptables-restore < /etc/iptables.rules
+carol::iptables-restore < /etc/iptables.rules
 moon::ipsec start
 carol::ipsec start
 carol::sleep 1