Permits running pylint without pylintrc.

pylint.py

 #!/usr/bin/env python
 # 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.
 
 """A wrapper script for using pylint from the command line."""
 
 import os
 import subprocess
 import sys
 
 
 _HERE = os.path.dirname(os.path.abspath(__file__))
 _PYLINT = os.path.join(_HERE, 'third_party', 'pylint.py')
 _RC_FILE = os.path.join(_HERE, 'pylintrc')
 
 
 # Run pylint. We prepend the command-line with the depot_tools rcfile. If
 # another rcfile is to be used, passing --rcfile a second time on the command-
 # line will work fine.
-command = [sys.executable, _PYLINT, '--rcfile=%s' % _RC_FILE] + sys.argv[1:]
+command = [sys.executable, _PYLINT]
+if os.path.isfile(_RC_FILE):
+  # The file can be removed to test 'normal' pylint behavior.
+  command.append('--rcfile=%s' % _RC_FILE)
+command.extend(sys.argv[1:])
 try:
   sys.exit(subprocess.call(command))
 except KeyboardInterrupt:
   sys.stderr.write('interrupted\n')
   sys.exit(1)