misc/ruby-additional.el: Remove functions implemented in Emacs 24.3.

* misc/ruby-additional.el (ruby-brace-to-do-end)
  (ruby-do-end-to-brace, ruby-toggle-block): Remove functions that
  are already in the latest released version of Emacs (24.3).
  [Bug #7565]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43475 b2dd03c8-39d4-4d8f-98ff-823fe69b080e