patch for accepts_nested_attributes_for and polymorphic belongs_to

I submitted a patch to fix the error message you get when you have a polymorphic belongs_to and you try to save a new record using accepts_nested_attributes_for.

http://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/2318-accepts_nested_attributes_for-raises-nomethoderror-when-saving-polymorphic-belongs_to

Thanks.
Mike