(MODULES-1174) Puppet 3.7 compatibility

 - Puppet 3.7 refactored underlying Win32 API code by changing gems and
   refactoring classes.  The windows-pr gem was removed which provides
   a number of methods and constants through mixins to the
   Puppet::Util::Windows::Security class.  A number of global constants
   are also defined in the namespaces ::Windows::File and
   ::Windows::Security.
 - Furthermore, some methods that used to be defined on
   Puppet::Util::Windows::Security are now in Puppet::Util::Windows::SID
 - Restructure the code to prefer Puppet 3.7 locations with a graceful
   fallback solution to 3.6.x with old gems, etc.
We could move the values in, sure.  It's simpler to read and makes the implementation less susceptible to things moving around in Puppet.

Also - I don't think there's a case for `windows-pr` to not have loaded based on how the checks are performed here.