Use gclient's git_cache setting in bot_update/api.py

recipe_modules/bot_update/example.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 = [
   'bot_update',
   'gclient',
   'recipe_engine/path',
   'recipe_engine/properties',
 ]
 
 def RunSteps(api):
   api.gclient.use_mirror = True
 
-  src_cfg = api.gclient.make_config()
+  src_cfg = api.gclient.make_config(GIT_MODE=True, CACHE_DIR='[GIT_CACHE]')
   soln = src_cfg.solutions.add()
   soln.name = 'src'
   soln.url = 'svn://svn.chromium.org/chrome/trunk/src'
   soln.revision = api.properties.get('revision')
   api.gclient.c = src_cfg
   api.gclient.c.revisions = api.properties.get('revisions', {})
   api.gclient.c.got_revision_mapping['src'] = 'got_cr_revision'
   patch = api.properties.get('patch', True)
   clobber = True if api.properties.get('clobber') else False
   force = True if api.properties.get('force') else False
@@ skipping 120 matching lines @@
   yield api.test('tryjob_v8') + api.properties(
       mastername='tryserver.chromium.linux',
       buildername='linux_rel',
       slavename='totallyaslave-c4',
       issue=12345,
       patchset=654321,
       patch_url='http://src.chromium.org/foo/bar',
       patch_project='v8',
       revisions={'src/v8': 'abc'}
   )