luci-py: Making __file__ usage unicode safe.

client/tests/isolate_format_test.py

 #!/usr/bin/env python
 # Copyright 2014 The LUCI Authors. All rights reserved.
 # Use of this source code is governed under the Apache License, Version 2.0
 # that can be found in the LICENSE file.
 
 import cStringIO
 import logging
 import os
 import sys
 import tempfile
 import unittest
 
-ROOT_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+ROOT_DIR = os.path.dirname(os.path.dirname(os.path.abspath(
+    __file__.decode(sys.getfilesystemencoding()))))
 sys.path.insert(0, ROOT_DIR)
 sys.path.insert(0, os.path.join(ROOT_DIR, 'third_party'))
 
 import isolate_format
 from depot_tools import auto_stub
 from depot_tools import fix_encoding
 from utils import file_path
 
 
 # Access to a protected member XXX of a client class
@@ skipping 971 matching lines @@
 
 
 if __name__ == '__main__':
   fix_encoding.fix_encoding()
   logging.basicConfig(
       level=logging.DEBUG if '-v' in sys.argv else logging.ERROR,
       format='%(levelname)5s %(filename)15s(%(lineno)3d): %(message)s')
   if '-v' in sys.argv:
     unittest.TestCase.maxDiff = None
   unittest.main()