ike-config: If we don't send a CFG_REQUEST, we don't expect a CFG_REPLY

Previously, attributes in an incorrectly sent CFG_REPLY would still be passed
to attribute handlers.  This does not prevent handlers from receiving
unrequested attributes if they requested at least one other.

src/libcharon/sa/ikev2/tasks/ike_config.c

@@ -317,6 +317,10 @@ METHOD(task_t, build_i, status_t,
 		{
 			message->add_payload(message, (payload_t*)cp);
 		}
+		else
+		{	/* we don't expect a CFG_REPLY */
+			return SUCCESS;
+		}
 	}
 	return NEED_MORE;
 }