Fix pylint error/bug on 'drmemory_factory'.

scripts/master/factory/drmemory_factory.py

 # Copyright (c) 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 ntpath
 import posixpath
 import re
 from buildbot.process import factory
 from buildbot.process.properties import WithProperties
 from buildbot.steps.source import SVN
@@ skipping 38 matching lines @@
 
 def BotToPlatform(bot_platform):
   """Takes a bot platform value and returns a platform string."""
   if bot_platform.startswith('win'):
     return 'windows'
   elif bot_platform.startswith('linux'):
     return 'linux'
   elif bot_platform.startswith('mac'):
     return 'mac'
   else:
-    raise ValueError('Unknown platform %s' % platform)
+    raise ValueError('Unknown platform %s' % bot_platform)
 
 
 def OsFullName(platform):
   if platform.startswith('win'):
     return 'Windows'
   elif platform.startswith('linux'):
     return 'Linux'
   elif platform.startswith('mac'):
     return 'MacOS'
   else:
@@ skipping 712 matching lines @@
     # TODO(rnk): We should run some selection of layout tests if we want to
     # verify output.
     ret.addStep(Test(command=cmd,
                      env={'CHROME_DEVEL_SANDBOX':
                           '/opt/chromium/chrome_sandbox'},
                      name=test,
                      descriptionDone=test,
                      description=test))
 
   return ret