adjust warn message that requested goal is already expired. (#1363)

Signed-off-by: Tomoya Fujita <Tomoya.Fujita@sony.com>

rclpy/rclpy/action/server.py

@@ -411,9 +411,10 @@ async def _execute_get_result_request(self, request_header_and_message):
             'Result request received for goal with ID: {0}'.format(goal_uuid))
 
         # If no goal with the requested ID exists, then return UNKNOWN status
+        # or the goal with the requested ID has been already expired
         if bytes(goal_uuid) not in self._goal_handles:
-            self._logger.debug(
-                'Sending result response for unknown goal ID: {0}'.format(goal_uuid))
+            self._logger.warn(
+                'Sending result response for unknown or expired goal ID: {0}'.format(goal_uuid))
             result_response = self._action_type.Impl.GetResultService.Response()
             result_response.status = GoalStatus.STATUS_UNKNOWN
             self._handle.send_result_response(request_header, result_response)