Remove ignored bot_update "force" parameter.

scripts/slave/recipes/v8/auto_roll_deps.py

 # 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.
 
 import base64
 
 DEPS = [
   'chromium',
   'depot_tools/bot_update',
   'depot_tools/gclient',
@@ skipping 103 matching lines @@
 
       return
 
     # Make it more likely to avoid inconsistencies when hitting different
     # mirrors.
     api.python.inline(
         'wait for consistency',
         'import time; time.sleep(20)',
     )
 
-    api.bot_update.ensure_checkout(force=True, no_shallow=True)
+    api.bot_update.ensure_checkout(no_shallow=True)
 
     # Get deps file from pending ref.
     pending_deps = api.gitiles.download_file(
         'https://chromium.googlesource.com/chromium/src',
         'DEPS',
         branch='refs/pending/heads/master',
         step_test_data= lambda: api.json.test_api.output({
           'value': base64.b64encode(TEST_DEPS_FILE % 'deadbeef'),
         }),
     )
@@ skipping 72 matching lines @@
               '{"results": [{"subject": "Update V8 to foo",' +
               ' "issue": 123456, "commit": false}]}'))
     )
   yield (api.test('inconsistent_state') +
       api.properties.generic(mastername='client.v8') +
       api.override_step_data(
           'git cat-file', api.raw_io.stream_output(
               TEST_DEPS_FILE % 'beefdead'))
     )