Add an assert to ensure UTF-8 locale when handling file paths.

client/tools/run_on_bots.py

 #!/usr/bin/env python
 # Copyright 2014 The Swarming 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.
 
 """Automated maintenance tool to run a script on bots.
 
 To use this script, write a self-contained python script (use a .zip if
 necessary), specify it on the command line and it will be packaged and triggered
 on all the swarming bots corresponding to the --dimension filters specified, or
 all the bots if no filter is specified.
 """
 
 __version__ = '0.1'
 
 import os
 import tempfile
 import shutil
 import subprocess
 import sys
 
 ROOT_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 
 # 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
 
 
 def get_bot_list(swarming_server, dimensions, dead_only):
   """Returns a list of swarming bots."""
   cmd = [
     sys.executable, 'swarming.py', 'bots',
     '--swarming', swarming_server,
     '--bare',
   ]
@@ skipping 21 matching lines @@
       f.write(str(isolate))
     shutil.copyfile(script, os.path.join(tempdir, base_script))
     cmd = [
       sys.executable, 'isolate.py', 'archive',
       '--isolate-server', isolate_server,
       '-i', isolate_file,
       '-s', isolated_file,
     ]
     return subprocess.check_output(cmd, cwd=ROOT_DIR).split()[0]
   finally:
-    shutil.rmtree(tempdir)
+    file_path.rmtree(tempdir)
 
 
 def run_serial(
     swarming_server, isolate_server, priority, deadline, repeat, isolated_hash,
     name, bots):
   """Runs the task one at a time.
 
   This will be mainly bound by task scheduling latency, especially if the bots
   are busy and the priority is low.
   """
@@ skipping 99 matching lines @@
       isolated_hash,
       name,
       bots)
 
 
 if __name__ == '__main__':
   fix_encoding.fix_encoding()
   tools.disable_buffering()
   colorama.init()
   sys.exit(main())