ike: Reuse interface ID during CHILD_SA rekeyings

src/libcharon/sa/ikev2/task_manager_v2.c

@@ -1874,6 +1874,8 @@ static void trigger_mbb_reauth(private_task_manager_t *this)
 		child_create->use_marks(child_create,
 								child_sa->get_mark(child_sa, TRUE).value,
 								child_sa->get_mark(child_sa, FALSE).value);
+		/* interface IDs are not migrated as the new CHILD_SAs on old and new
+		 * IKE_SA go though regular updown events */
 		new->queue_task(new, &child_create->task);
 		children = TRUE;
 	}