update ocr demo

python/examples/pipeline/ocr/hybrid_service_pipeline_server.py

@@ -131,6 +131,6 @@ response_op = ResponseOp(input_ops=[rec_op])
 
 server = PipelineServer()
 server.set_response_op(response_op)
-server.start_local_rpc_service()  # add this line
 server.prepare_server('config.yml')
+server.start_local_rpc_service()  # add this line
 server.run_server()

python/examples/pipeline/ocr/local_service_pipeline_server.py

@@ -130,6 +130,6 @@ response_op = ResponseOp(input_ops=[rec_op])
 
 server = PipelineServer()
 server.set_response_op(response_op)
-server.start_local_rpc_service()  # add this line
 server.prepare_server('config.yml')
+server.start_local_rpc_service()  # add this line
 server.run_server()

python/examples/pipeline/ocr/pipeline_http_client.py

@@ -18,9 +18,6 @@ import json
 import cv2
 import base64
 import os
-import time
-import util
-import multiprocessing
 
 
 def cv2_to_base64(image):