Make bot_update on win more resilient

recipe_modules/bot_update/resources/bot_update.py

 #!/usr/bin/env python
 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # TODO(hinoka): Use logging.
 
 import cStringIO
 import codecs
 import copy
@@ skipping 500 matching lines @@
 
         if not path.isdir(sln_dir):
           git(*clone_cmd)
         else:
           git('remote', 'set-url', 'origin', mirror_dir, cwd=sln_dir)
           git('fetch', 'origin', cwd=sln_dir)
         for ref in refs:
           refspec = '%s:%s' % (ref, ref.lstrip('+'))
           git('fetch', 'origin', refspec, cwd=sln_dir)
 
+        # Windows sometimes has trouble deleting files.
+        # This can make git commands that rely on locks fail.
+        if sys.platform.startswith('win'):
+          call('gclient.bat', 'cleanup', '--break_repo_locks')

[ddoman1, 2016/10/25 21:55:23]

I am afraid that it may be a better choice to copy & paste "def
_maybe_break_locks()" from gclient_scm.py to bot_update.py.

#1. CMDcleanup() has been marked as deprecated
:
https://chromium.googlesource.com/chromium/tools/depot_tools.git/+/master/gcl...

#2. invoking gclient within git_checkout() may fail.

From
https://chromium.googlesource.com/chromium/tools/depot_tools.git/+/master/rec...

" # Get a checkout of each solution, without DEPS or hooks.
  # Calling git directly because there is no way to run Gclient without
  # invoking DEPS."

[agable, 2016/10/28 16:55:34]

I'm the one deprecating cleanup (which has always previously been a no-op for
Git), so I told Katie to take this approach.
This is unfortunately a really good point. Nothing else in this git_checkouts
function invokes gclient, and that's probably on purpose. Dang.

[katthomas, 2016/10/28 23:40:29]

Done.

+
         revision = get_target_revision(name, url, revisions) or 'HEAD'
         force_revision(sln_dir, revision)
         done = True
       except SubprocessFailed as e:
         # Exited abnormally, theres probably something wrong.
         print 'Something failed: %s.' % str(e)
 
         if time.time() > deadline:
           overrun = time.time() - deadline
           print 'Ran %s seconds past deadline. Aborting.' % overrun
@@ skipping 565 matching lines @@
     # download patch failure is still an infra problem.
     if e.code == 3:
       # Patch download problem.
       return 87
     # Genuine patch problem.
     return 88
 
 
 if __name__ == '__main__':
   sys.exit(main())