Make all the rest of the recipes explicitly specify GIT_MODE

scripts/slave/recipes/perf/telemetry_harness_upload.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 = [
   'depot_tools/bot_update',
   'chromium',
   'file',
   'depot_tools/gclient',
   'gsutil',
   'recipe_engine/path',
   'recipe_engine/properties',
   'recipe_engine/step',
 ]
 
 
 def RunSteps(api):
   kwargs = {}
   kwargs['TARGET_PLATFORM'] = 'android'
   kwargs['TARGET_ARCH'] = 'arm'
 
   api.chromium.set_config('chromium', **kwargs)
-  api.gclient.set_config('chromium', **kwargs)
+  api.gclient.set_config('chromium', GIT_MODE=True, **kwargs)
   api.gclient.apply_config('android')
   step_result = api.bot_update.ensure_checkout()
   # Whatever step is run right before this line needs to emit got_revision.
   got_revision = step_result.presentation.properties['got_revision']
 
   harness_file = 'telemetry-%s.zip' % got_revision
   harness_path = api.path.mkdtemp('telemetry-harness')
 
   api.step('create harness archive', [
                    api.path['checkout'].join(
@@ skipping 12 matching lines @@
   api.file.rmtree('remove harness temp directory', harness_path)
 
 
 def GenTests(api):
   yield (
       api.test('basic') +
       api.properties.generic(
           mastername='chromium.lkgr',
           buildername='Telemetry Harness Upload')
   )