IKEv2 mobike initiator support. road is the initiator and migrates sa.

Road has one IP addresses at start. Remove the ip adddress
after the IPsec connection is established. Pluto will detect address change
and, fail to find an alternative source adddress.

Later on a new address is added. Pluto will detect new address and
send MOBIKE probe.  When the mobike response arrive migrate the SA.

The right subnet on road is 0/0