Remove ignored bot_update "force" parameter.

scripts/slave/recipes/webrtc/auto_roll_webrtc_deps.py

 # Copyright 2015 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',
   'recipe_engine/path',
@@ skipping 15 matching lines @@
         step_test_data=lambda: api.raw_io.test_api.stream_output(
             '1', stream='stdout')
   )
   step_result.presentation.logs['stdout'] = step_result.stdout.splitlines()
   if step_result.stdout.strip() != '1':
     step_result.presentation.step_text = 'Rolling deactivated'
     return
   else:
     step_result.presentation.step_text = 'Rolling activated'
 
-  api.bot_update.ensure_checkout(force=True)
+  api.bot_update.ensure_checkout()
   api.gclient.runhooks()
 
   # Enforce a clean state.
   api.git(
       'checkout', '-f', 'master',
       cwd=api.path['checkout'],
   )
   api.git(
       'clean', '-ffd',
       cwd=api.path['checkout'],
@@ skipping 15 matching lines @@
       api.test('rolling_activated') +
       api.properties.generic(mastername='client.webrtc.fyi',
                              buildername='Auto-roll - WebRTC DEPS')
   )
   yield (api.test('rolling_deactivated') +
       api.properties.generic(mastername='client.webrtc.fyi',
                              buildername='Auto-roll - WebRTC DEPS') +
       api.override_step_data('check roll status',
                              api.raw_io.stream_output('0', stream='stdout'))
   )