[Telemetry] Resolve errors due to new pylint checker.

tools/telemetry/telemetry/core/browser_options_unittest.py

 # Copyright 2012 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.
 import optparse
 import os
 import unittest
 
 from telemetry.core import browser_options
 
 
@@ skipping 64 matching lines @@
     current_dir = os.path.dirname(__file__)
     parser.parse_args(['--browser', 'any', '--profile-dir', current_dir])
     self.assertEquals(options.browser_options.profile_dir, current_dir)
 
   def testExtraBrowserArgs(self):
     options = browser_options.BrowserFinderOptions()
     parser = options.CreateParser()
     parser.parse_args(['--extra-browser-args=--foo --bar'])
 
     self.assertEquals(options.browser_options.extra_browser_args,
-                      set(['--foo','--bar']))
+                      set(['--foo', '--bar']))
 
   def testUseDevToolsActivePort(self):
     options = browser_options.BrowserFinderOptions()
     parser = options.CreateParser()
     parser.parse_args(['--use-devtools-active-port'])
 
     self.assertEquals(options.browser_options.use_devtools_active_port, True)
 
   def testMergeDefaultValues(self):
     options = browser_options.BrowserFinderOptions()
@@ skipping 13 matching lines @@
 
     options.MergeDefaultValues(parser.get_default_values())
 
     self.assertTrue(options.already_true)
     self.assertFalse(options.already_false)
     self.assertTrue(options.unset is None)
     self.assertTrue(options.default_true)
     self.assertFalse(options.default_false)
     self.assertFalse(options.override_to_true)
     self.assertTrue(options.override_to_false)