added ikev2/dhcp-dynamic scenario

testing/tests/ikev2/dhcp-dynamic/pretest.dat

@@ -0,0 +1,12 @@
+moon::/etc/init.d/iptables start 2> /dev/null
+carol::/etc/init.d/iptables start 2> /dev/null
+dave::/etc/init.d/iptables start 2> /dev/null
+venus::cat /etc/dhcpd.conf
+venus::/etc/init.d/dhcpd start 2> /dev/null
+carol::ipsec start
+dave::ipsec start
+moon::ipsec start
+carol::sleep 2 
+carol::ipsec up home
+dave::ipsec up home
+carol::sleep 1