This scenario tests make-before-break reauthentication using overlapping
IKE_SAs by setting the make_before_break strongswan.conf option. The
initiator carol reauthenticates the IKE_SA with host moon using
ikelifetime=10s, but does not close the old IKE_SA before the replacement
CHILD_SA is in place. A constant ping from carol to client alice
hiding in the subnet behind moon tests if the CHILD_SA works during the
whole procedure.