Fix VS2008 build by adding a warning ignore.

R=maruel
BUG=2528
TEST=Building with VS2008 should succeed.

Review URL: http://codereview.chromium.org/113270

git-svn-id: http://src.chromium.org/svn/trunk/src/build@15859 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

common.gypi

@@ -377,7 +377,7 @@
           '$(VSInstallDir)/VC/atlmfc/include',
         ],
         'msvs_cygwin_dirs': ['../third_party/cygwin'],
-        'msvs_disabled_warnings': [4503, 4819],
+        'msvs_disabled_warnings': [4396, 4503, 4819],
         'msvs_settings': {
           'VCCLCompilerTool': {
             'MinimalRebuild': 'false',