Add just code style.

python/paddle_serving_app/utils/arr2image.py

@@ -11,10 +11,12 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# pylint: disable=doc-string-missing
 
 import cv2
 import yaml
 
+
 class Arr2Image(object):
     """
     from numpy array image(jpeg) to cv::Mat image

python/util.py

@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+# pylint: disable=doc-string-missing
 
 from pkg_resources import DistributionNotFound, get_distribution
 from grpc_tools import protoc