Interop with strongswan, original IKE responder, rekeying IKE.

East, libreswan, is the original IKE initiator with auto=start.
West, strongswan, is the original IKE responder. West will rekey the IKE SA using
CREATE_CHILD_SA exchange  RFC 7296 #1.3.2
The libreswan, east, is the original initiator and the responder to Child rekey.

Strongswan IKE SA rekey is triggered after 20 seconds
