Fix detection of Visual Studio version.
Fix detection of Visual Studio version.

BUG=None
TEST=None
Review URL: http://codereview.chromium.org/2848040/show

old8xp/gyp_from_google,old8xp/gyp_from_google,old8xp/gyp_from_google,old8xp/gyp_from_google,old8xp/gyp_from_google