luci-py: Making __file__ usage unicode safe.

client/tests/swarming_smoke_test.py

 #!/usr/bin/env python
 # Copyright 2013 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 logging
 import os
 import subprocess
 import sys
 import unittest
 
-BASE_DIR = os.path.dirname(os.path.abspath(__file__))
+BASE_DIR = os.path.dirname(os.path.abspath(
+    __file__.decode(sys.getfilesystemencoding())))
 
 ISOLATE_SERVER = 'https://isolateserver.appspot.com/'
 SWARMING_SERVER = 'https://chromium-swarm.appspot.com/'
 
 
 class TestSwarm(unittest.TestCase):
   def test_example(self):
     # pylint: disable=W0101
     # A user should be able to trigger a swarm job and return results.
     cmd = [
@@ skipping 14 matching lines @@
     logging.debug(out)
     self.assertEqual(0, p.returncode, out)
 
 
 if __name__ == '__main__':
   logging.basicConfig(
       level=logging.DEBUG if '-v' in sys.argv else logging.ERROR)
   if '-v' in sys.argv:
     unittest.TestCase.maxDiff = None
   unittest.main()