Replace check_output() call site into check_call(). Would throw otherwise.

scm.py

 # Copyright (c) 2011 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.
 
 """SCM-specific utility classes."""
 
 import cStringIO
 import glob
 import logging
 import os
@@ skipping 58 matching lines @@
   """Similar to upload.py's version but much simpler.
 
   Returns 'svn', 'git' or None.
   """
   if os.path.isdir(os.path.join(root, '.svn')):
     return 'svn'
   elif os.path.isdir(os.path.join(root, '.git')):
     return 'git'
   else:
     try:
-      subprocess2.check_output(
+      subprocess2.check_call(
           ['git', 'rev-parse', '--show-cdup'],
           stdout=subprocess2.VOID,
           stderr=subprocess2.VOID,
           cwd=root)
       return 'git'
     except (OSError, subprocess2.CalledProcessError):
       return None
 
 
 class GIT(object):
@@ skipping 893 matching lines @@
       if (file_status[0][0] in ('D', 'A', '!') or
           not file_status[0][1:].isspace()):
         # Added, deleted file requires manual intervention and require calling
         # revert, like for properties.
         try:
           SVN.Capture(['revert', file_status[1]], cwd=repo_root)
         except subprocess2.CalledProcessError:
           if not os.path.exists(file_path):
             continue
           raise