Demove dead code that is never used in Windows Vista or later

Now that Mozc for Windows does not support Windows XP, we can safely get rid of SystemUtil::IsVistaOrLater() as well as the dead code conditionally used behind that.

This is just dead-code removal.  No behavior change is intended.

BUG=none
TEST=unittest

git-svn-id: https://mozc.googlecode.com/svn/trunk@523 a6090854-d499-a067-5803-1114d4e51264
31 files changed
tree: 9cf83bd1d7bc097e83c075d7750093ff63394a3a
  1. src/