fix create predictor by desc bug

python/paddle_serving_client/__init__.py

@@ -105,7 +105,7 @@ class Client(object):
         predictor_sdk.set_server_endpoints(endpoints)
         sdk_desc = predictor_sdk.gen_desc()
         timestamp = time.asctime(time.localtime(time.time()))
-        self.client_handle_.create_predictor(sdk_desc)
+        self.client_handle_.create_predictor_by_desc(sdk_desc)
 
     def get_feed_names(self):
         return self.feed_names_

python/paddle_serving_client/io/__init__.py

@@ -80,9 +80,9 @@ def save_model(server_model_folder,
     with open("{}/serving_server_conf.prototxt".format(server_model_folder), "w") as fout:
         fout.write(str(config))
     with open("{}/serving_client_conf.stream.prototxt".format(client_config_folder), "wb") as fout:
-        fout.write(config.serialize_to_string())
+        fout.write(config.SerializeToString())
     with open("{}/serving_server_conf.stream.prototxt".format(server_model_folder), "wb") as fout:
-        fout.write(config.serialize_to_string())
+        fout.write(config.SerializeToString())