gclient: Don't change directories when checking git version.

gclient_scm.py

 # Copyright (c) 2009 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.
 
 """Gclient-specific SCM-specific operations."""
 
 import logging
 import os
 import re
 import subprocess
@@ skipping 175 matching lines @@
       self._Run(['diff', '--name-status', merge_base], redirect_stdout=False)
       files = self._Run(['diff', '--name-only', merge_base]).split()
       file_list.extend([os.path.join(self.checkout_path, f) for f in files])
 
   def _CheckMinVersion(self, min_version):
     def only_int(val):
       if val.isdigit():
         return int(val)
       else:
         return 0
-    version = self._Run(['--version']).split()[-1]
+    version = self._Run(['--version'], cwd='.').split()[-1]
     version_list = map(only_int, version.split('.'))
     min_version_list = map(int, min_version.split('.'))
     for min_ver in min_version_list:
       ver = version_list.pop(0)
       if min_ver > ver:
         raise gclient_utils.Error('git version %s < minimum required %s' %
                                   (version, min_version))
       elif min_ver < ver:
         return
 
@@ skipping 272 matching lines @@
           self.ReplaceAndPrint(line)
         else:
           if (line.startswith(self.original_prefix) or
               line.startswith(self.working_prefix)):
             self.ReplaceAndPrint(line)
           else:
             print line
 
     filterer = DiffFilterer(self.relpath)
     self.RunAndFilterOutput(command, path, False, False, filterer.Filter)