[Telemetry + tools/perf] Modify the pylint disable message to use symbolic name

tools/perf/metrics/speedindex_unittest.py

 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # These tests access private methods in the speedindex module.
-# pylint: disable=W0212
+# pylint: disable=protected-access
 
 import unittest
 
 from telemetry.util import color_histogram
 from telemetry.util import rgba_color
 
 from metrics import speedindex
 
 
 class FakeImageUtil(object):
-  # pylint: disable=W0613
+  # pylint: disable=unused-argument
   def GetColorHistogram(self, image, ignore_color=None, tolerance=None):
     return image.ColorHistogram()
 
 
 class FakeVideo(object):
   def __init__(self, frames):
     self._frames = frames
 
   def GetVideoFrameIter(self):
     for frame in self._frames:
       yield frame
 
 class FakeBitmap(object):
   def __init__(self, r, g, b):
     self._histogram = color_histogram.ColorHistogram(r, g, b, rgba_color.WHITE)
 
-  # pylint: disable=W0613
+  # pylint: disable=unused-argument
   def ColorHistogram(self, ignore_color=None, tolerance=None):
     return self._histogram
 
 
 class FakeTab(object):
   def __init__(self, video_capture_result=None):
     self._javascript_result = None
     self._video_capture_result = FakeVideo(video_capture_result)
 
   @property
@@ skipping 66 matching lines @@
     self.assertEqual(time_completeness[2], (0.2, 0.0))
     self.assertEqual(time_completeness[3], (0.3, 1.0))
 
   def assertTimeCompleteness(self, time_completeness, time, completeness):
     self.assertEqual(time_completeness[0], time)
     self.assertAlmostEqual(time_completeness[1], completeness)
 
 
 if __name__ == "__main__":
   unittest.main()