Remove ignored bot_update "force" parameter.

scripts/slave/recipes/mojo.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.
 
 DEPS = [
   'adb',
   'depot_tools/bot_update',
   'depot_tools/gclient',
   'goma',
   'recipe_engine/json',
   'recipe_engine/path',
   'recipe_engine/platform',
   'recipe_engine/properties',
   'recipe_engine/python',
   'recipe_engine/step',
   'depot_tools/tryserver',
   'url',
 ]
 
 
 def _CheckoutSteps(api, buildername):
   # Checkout mojo and its dependencies (specified in DEPS) using gclient
   api.gclient.set_config('mojo')
   if 'Android' in buildername:
     api.gclient.apply_config('android')
-  api.bot_update.ensure_checkout(force=True)
+  api.bot_update.ensure_checkout()
   api.gclient.runhooks()
 
 
 def _BuildSteps(api, buildername, is_debug, is_official):
   mojob_path = api.path['checkout'].join('mojo', 'tools', 'mojob.py')
   args = []
   gn_args = []
   if 'Android' in buildername:
     args += ['--android']
 
@@ skipping 252 matching lines @@
             "usb_status": True,
           },
           {}
         ]))
     yield test
   yield(api.test('mojo_linux_try') +
       api.properties.tryserver(buildername="Mojo Linux Try"))
   yield(api.test('mojo_android_builder_tests_dbg_fail_device_check') +
       api.properties.tryserver(buildername="Mojo Android Builder Tests (dbg)") +
       api.step_data("device_status", retcode=1))