Remove ignored bot_update "force" parameter.

scripts/slave/recipe_modules/chromium_android/api.py

 # Copyright 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.
 
 import contextlib
 import datetime
 import json
 import os
 import pipes
 import re
@@ skipping 105 matching lines @@
     s.managed = self.c.managed
     s.revision = self.c.revision
     spec.revisions = self.c.revisions
 
     self.m.gclient.break_locks()
     refs = self.m.properties.get('event.patchSet.ref')
     if refs:
       refs = [refs]
     if use_bot_update:
       result = self.m.bot_update.ensure_checkout(
-          spec, refs=refs, with_branch_heads=with_branch_heads, force=True)
+          spec, refs=refs, with_branch_heads=with_branch_heads)
     else:
       result = self.m.gclient.checkout(
           spec, with_branch_heads=with_branch_heads)
 
     # TODO(sivachandra): Manufacture gclient spec such that it contains "src"
     # solution + repo_name solution. Then checkout will be automatically
     # correctly set by gclient.checkout
     self.m.path['checkout'] = self.m.path['slave_build'].join('src')
 
     self.clean_local_files()
@@ skipping 1361 matching lines @@
       script = self.c.test_runner
       if wrapper_script_suite_name:
         script = self.m.chromium.output_dir.join('bin', 'run_%s' %
                                                  wrapper_script_suite_name)
       else:
         env = kwargs.get('env', {})
         env['CHROMIUM_OUTPUT_DIR'] = env.get('CHROMIUM_OUTPUT_DIR',
                                              self.m.chromium.output_dir)
         kwargs['env'] = env
       return self.m.python(step_name, script, args, **kwargs)