(FACT-570) Update FFI, Win32-Security, Win32-Dir

 - Upgrade FFI gem to 1.9.3 from 1.91
 - Upgrade win32-security gem to 0.2.5 from 0.1.4
 - Upgrade win32-dir gem to 0.4.8 from 0.4.3
Since this is a dev dependency I think we're good on what we have for `sys-admin`.  Ultimately, we can yank it for Puppet development.