message: fix doc bug
  fix doc bug
diff: @@ -111,7 +111,7 @@ After the -- model parameter, the folder path of multiple model files is passed
  #for cpu user
  python -m paddle_serving_server.serve --model ocr_det_model ocr_rec_model --port 9293
  #for gpu user
  -python -m paddle_serving_server_gpu.serve --model ocr_det_model ocr_rec_model --port 9293 --gpu_id 0
  +python -m paddle_serving_server.serve --model ocr_det_model ocr_rec_model --port 9293 --gpu_id 0
  ```
  ### Client Prediction
  