controller: Don't listen for CHILD_SA state changes when terminating IKE_SAs

We actually want to wait until the IKE_SA is destroyed, not any of the
CHILD_SAs (even though there might not be that much of a difference
depending on the number of CHILD_SAs).

Fixes #2261.

src/libcharon/control/controller.c

@@ -588,7 +588,6 @@ METHOD(controller_t, terminate_ike, status_t,
 		.listener = {
 			.public = {
 				.ike_state_change = _ike_state_change_terminate,
-				.child_state_change = _child_state_change_terminate,
 			},
 			.logger = {
 				.public = {