Revert "Make marshal_load public"

This reverts commit ee7cc6ac35.

I'm not sure I agree with the spec, but I just tweaked it.

lib/ostruct.rb

@@ -203,7 +203,6 @@ class OpenStruct
   # Provides marshalling support for use by the Marshal library.
   #
   alias_method :marshal_load, :update_to_values! # :nodoc:
-  public :marshal_load
 
   #
   # Used internally to defined properties on the

spec/ruby/library/openstruct/marshal_load_spec.rb

@@ -4,7 +4,7 @@ require "ostruct"
 describe "OpenStruct#marshal_load when passed [Hash]" do
   it "defines methods based on the passed Hash" do
     os = OpenStruct.new
-    os.marshal_load(age: 20, name: "John")
+    os.send :marshal_load, age: 20, name: "John"
 
     os.age.should eql(20)
     os.name.should == "John"