Remove ignored bot_update "force" parameter.

scripts/slave/recipes/run_presubmit.py

 # Copyright (c) 2013 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.
 
 DEPS = [
   'depot_tools/bot_update',
   'depot_tools/gclient',
   'depot_tools/git',
   'depot_tools/presubmit',
   'recipe_engine/json',
   'recipe_engine/path',
   'recipe_engine/properties',
   'recipe_engine/python',
   'recipe_engine/step',
   'depot_tools/tryserver',
   'depot_tools/rietveld',
   'v8',
   'webrtc',
 ]
 
 
 def _RunStepsInternal(api):
   repo_name = api.properties['repo_name']
   codereview_auth = api.properties.get('codereview_auth', False)
-  force_checkout = api.properties.get('force_checkout', False)
   patch_storage = api.properties.get('patch_storage', 'rietveld')
 
   api.gclient.set_config(repo_name)
 
   kwargs = {}
   bot_update_step = api.bot_update.ensure_checkout(
-      force=force_checkout,
       patch_oauth2=codereview_auth,
       **kwargs)
   relative_root = api.gclient.calculate_patch_root(
       api.properties['patch_project']).rstrip('/')
   got_revision_property = api.gclient.c.got_revision_mapping[relative_root]
   upstream = bot_update_step.json.output['properties'].get(
       got_revision_property)
 
   abs_root = api.path['slave_build'].join(relative_root)
   # TODO(hinoka): Extract email/name from issue?
@@ skipping 172 matching lines @@
 
   yield (
     api.test('presubmit-infra-failure') +
     api.properties.tryserver(
         mastername='tryserver.chromium.linux',
         buildername='chromium_presubmit',
         repo_name='chromium',
         patch_project='chromium') +
     api.step_data('presubmit', api.json.output({}, retcode=2))
   )