value.rb: remove DL

* ext/fiddle/lib/fiddle/value.rb (Fiddle::ValueUtil#wrap_arg): remove
  deprecated require.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38019 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/fiddle/lib/fiddle/value.rb

@@ -46,8 +46,6 @@ module Fiddle
     end
 
     def wrap_arg(arg, ty, funcs = [], &block)
-        require 'dl/func'
-
         funcs ||= []
         case arg
         when nil