[BUG] nested blocks aren't protected on export

["Eric Schulte" <schulte.eric@gmail.com>]

Hi,

When exporting nested blocks, the results of the inner blocks are not
fully protected from further exportation.  For example, the following
org-mode text

--8<---------------cut here---------------start------------->8---
** protecting block bodies
#+begin_src org
  ,#+begin_src emacs-lisp
  ,  (message "something")
  ,#+end_src
#+end_src
--8<---------------cut here---------------end--------------->8---

exports to the following LaTeX

--8<---------------cut here---------------start------------->8---
\section*{protecting block bodies}
\label{sec-1}

\begin{verbatim}
  (message "something")
\end{verbatim}
--8<---------------cut here---------------end--------------->8---

in which it looks like the "#+begin_src emacs-lisp" and the "#+end_src"
lines are completely removed, and exports to the following html
(newlines added for readability)

--8<---------------cut here---------------start------------->8---
<pre class="src src-org">
<span class="org-org-meta-line">#+begin_src emacs-lisp</span>
<span class="org-org-block">  (message "something")</span>
<span class="org-org-meta-line">
</pre>
--8<---------------cut here---------------end--------------->8---

in which the #+begin_src line is in tact, but it appears everything
following the end_src line (including the </span>) is removed.

I've played around with adding 'org-protected properties during export
but to no avail.

Any suggestions are much appreciated.

Thanks -- Eric