Make syzygy recipes explicitly set GIT_MODE

scripts/slave/recipes/syzygy/kasko_official.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.
 
 """Buildbot recipe definition for the official Kasko builder.
 
 To be tested using a command-line like:
 
   /build/scripts/tools/run_recipe.py syzygy/official_kasko
       revision=0e9f25b1098271be2b096fd1c095d6d907cf86f7
@@ skipping 29 matching lines @@
 
 def RunSteps(api, buildername):
   """Generates the sequence of steps that will be run by the slave."""
   assert buildername in _BUILDERS
 
   # Configure the build environment.
   s = api.syzygy
   config, kwargs = _BUILDERS[buildername]
   s.set_config(config, **kwargs)
   api.chromium.set_config(config, **kwargs)
-  api.gclient.set_config(config, **kwargs)
+  api.gclient.set_config(config, GIT_MODE=True, **kwargs)
 
   # Clean up any running processes on the slave.
   s.taskkill()
 
   # Checkout and compile the project.
   s.checkout()
   s.runhooks()
   s.compile()
 
   # Load and run the unittests.
   unittests = s.read_unittests_gypi()
   s.run_unittests(unittests)
 
   build_config = api.chromium.c.BUILD_CONFIG
 
   assert s.c.official_build
 
   assert build_config == 'Release'
   s.archive_binaries()
   s.upload_kasko_symbols()
 
 
 def GenTests(api):
   """Generates an end-to-end successful test for each builder."""
   for buildername in _BUILDERS.iterkeys():
     yield api.syzygy.generate_test(api, buildername)