fix codestyle

doc/PIPELINE_SERVING.md

@@ -581,4 +581,3 @@ Take imdb model ensemble as an example:
 ```shell
 curl -X POST -k http://localhost:8080/v1/example/echo -d '{"key": ["words"], "value": ["i am very sad | 0"]}'
 ```
-

doc/PIPELINE_SERVING_CN.md

@@ -578,4 +578,3 @@ go build <filename>.go
 ```shell
 curl -X POST -k http://localhost:8080/v1/example/echo -d '{"key": ["words"], "value": ["i am very sad | 0"]}'
 ```
-

python/pipeline/dag.py

@@ -299,7 +299,6 @@ class DAGExecutor(object):
             sys.stderr.write(profile_str)
 
         # add profile info into rpc_resp
-        profile_value = ""
         if resp_channeldata.client_need_profile:
             profile_set = resp_channeldata.profile_data_set
             profile_set.add(profile_str)