Make Kernel.Pathname as public again

Author: hsbt

lib/pathname.rb

@@ -1219,8 +1219,12 @@ module Kernel
   #
   # This method is available since 1.8.5.
   def Pathname(path) # :doc:
+    Kernel.Pathname(path)
+  end
+  private :Pathname
+
+  def self.Pathname(path) # Compatibility for C version
     return path if Pathname === path
     Pathname.new(path)
   end
-  private :Pathname
 end