Set msvs_cygwin_shell default to 0

This will cause all actions which do not have 'msvs_cygwin_shell': 1 
to be run under cmd.exe.

BUG=158680,123026

Review URL: https://chromiumcodereview.appspot.com/11941002

git-svn-id: http://src.chromium.org/svn/trunk/src/build@178146 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

common.gypi

@@ -3753,6 +3753,7 @@
           '$(VSInstallDir)/VC/atlmfc/include',
         ],
         'msvs_cygwin_dirs': ['<(DEPTH)/third_party/cygwin'],
+        'msvs_cygwin_shell': 0,
         'msvs_disabled_warnings': [4351, 4396, 4503, 4819,
           # TODO(maruel): These warnings are level 4. They will be slowly
           # removed as code is fixed.