Fix pylint warnings

PythonClient/.pylintrc

@@ -1,4 +1,4 @@
 [TYPECHECK]
 ignore=carla_server_pb2.py
 ignored-modules=ConfigParser,numpy,numpy.random,pygame,shutil
-ignored-classes=_socketobject,EpisodeReady
+ignored-classes=_socketobject,EpisodeReady,SceneDescription,Sensor

PythonClient/carla/sensor.py

@@ -7,15 +7,15 @@
 """CARLA sensors."""
 
 
-import json
 import os
 
+from collections import namedtuple
+
 try:
     import numpy
 except ImportError:
     raise RuntimeError('cannot import numpy, make sure numpy package is installed.')
 
-from collections import namedtuple
 from .transform import Transform, Translation, Rotation, Scale
 
 # ==============================================================================