ike-sa-manager: Signal waiting threads after check out/in for uniqueness check

Fixes 758b1caa0e ("ikev1: Prevent deadlock when checking for duplicate IKEv1 SAs")

src/libcharon/sa/ike_sa_manager.c

@@ -1646,6 +1646,9 @@ METHOD(ike_sa_manager_t, checkin, void,
 				 * need for a lookup via get_entry_by... */
 				lock_single_segment(this, segment);
 				entry->checked_out = FALSE;
+				/* We already signaled waiting threads above, we have to do that
+				 * again after checking the SA out and back in again. */
+				entry->condvar->signal(entry->condvar);
 			}
 		}