luci-py: Making __file__ usage unicode safe.

client/tools/run_swarming_tests_on_swarming.py

 #!/usr/bin/env python
 # Copyright 2012 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.
 
 """Runs the whole set of swarming client unit tests on swarming itself.
 
 This is done in a few steps:
   - Archive the whole directory as a single .isolated file.
   - Create one test-specific .isolated for each test to run. The file is created
     directly and archived manually with isolateserver.py.
   - Trigger each of these test-specific .isolated file per OS.
   - Get all results out of order.
 """
 
 __version__ = '0.1'
 
 import glob
 import logging
 import os
 import subprocess
 import sys
 import tempfile
 import time
 
-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()))))
 
 # Must be first import.
 import parallel_execution
 
 from third_party import colorama
 from third_party.depot_tools import fix_encoding
 from utils import file_path
 from utils import tools
 
 
@@ skipping 170 matching lines @@
       tests,
       options.logs,
       options.no_idempotent)
 
 
 if __name__ == '__main__':
   fix_encoding.fix_encoding()
   tools.disable_buffering()
   colorama.init()
   sys.exit(main())