Revert "(PUP-391) Fix Rdoc 4+ specs on Windows Ruby 2 x64"

This reverts commit 6767686.

As we are removing the Dir (win32/dir) monkeypatches, this workaround is
no longer needed.

Author: GabrielNagy

lib/puppet/util/rdoc.rb

@@ -26,13 +26,6 @@ def rdoc(outputdir, files, charset = nil)
 
     options << "--force-update"
     options += [ "--charset", charset] if charset
-    # Rdoc root default is Dir.pwd, but the win32-dir gem monkey patches Dir.pwd
-    # replacing Ruby's normal / with \.  When RDoc generates relative paths it
-    # uses relative_path_from that will generate errors when the slashes don't
-    # properly match.  This is a workaround for that issue.
-    if Puppet::Util::Platform.windows? && RDoc::VERSION !~ /^[0-3]\./
-      options += [ "--root", Dir.pwd.tr('\\', '/')]
-    end
     options += files
 
     # launch the documentation process