use iptables-restore in all ikev2 firewall scenarios

testing/tests/ikev2/ip-pool/posttest.dat

@@ -1,6 +1,6 @@
 carol::ipsec stop
 dave::ipsec stop
 moon::ipsec stop
-moon::/etc/init.d/iptables stop 2> /dev/null
-carol::/etc/init.d/iptables stop 2> /dev/null
-dave::/etc/init.d/iptables stop 2> /dev/null
+moon::iptables-restore < /etc/iptables.flush
+carol::iptables-restore < /etc/iptables.flush
+dave::iptables-restore < /etc/iptables.flush