luci-py: Making __file__ usage unicode safe.

client/libs/logdog/tests/varint_test.py

 #!/usr/bin/env python
 # Copyright 2016 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 itertools
 import os
 import sys
 import unittest
 import StringIO
 
 ROOT_DIR = os.path.dirname(os.path.abspath(os.path.join(
-    __file__, os.pardir, os.pardir, os.pardir)))
+    __file__.decode(sys.getfilesystemencoding()),
+    os.pardir, os.pardir, os.pardir)))
 sys.path.insert(0, ROOT_DIR)
 
 from libs.logdog import varint
 
 
 class VarintTestCase(unittest.TestCase):
 
   def testVarintEncodingRaw(self):
     for base, exp in (
         (0, b'\x00'),
@@ skipping 33 matching lines @@
             "Decoded length (%d) doesn't match expected (%d)" % (
                 count, len(sio.getvalue())))
 
         if perm == 0:
           break
         perm = perm[1:]
 
 
 if __name__ == '__main__':
   unittest.main()