Fix bug with emphasis-like expressions in example blocks

Martin Skjaeveland writes:

> Hi all,
>
> when I import the file
>
> --8<---------------cut here---------------start------------->8---
> -----------------
> | grandmother   |
> =================
> | sim:Jackeline |
> | sim:Mona      |
> -----------------
> --8<---------------cut here---------------end------------->8---
>
> using the command
>
> #+INCLUDE "grandmothers.txt" example
>
> and export to latex it turns into
>
>
> \begin{verbatim}
> -----------------
> | grandmother   |
> \texttt{===============}
> | sim:Jackeline |
> | sim:Mona      |
> -----------------
> \end{verbatim}
>
>
> I would like to remove \texttt{ }. I have tried different export
> option settings, but I can't make it work.
>

lisp/org-exp.el

@@ -1688,9 +1688,10 @@ from the buffer."
   "Mark verbatim snippets with the protection property."
   (goto-char (point-min))
   (while (re-search-forward org-verbatim-re nil t)
-    (add-text-properties (match-beginning 4) (match-end 4)
-			 '(org-protected t org-verbatim-emph t))
-    (goto-char (1+ (match-end 4)))))
+    (org-if-unprotected
+     (add-text-properties (match-beginning 4) (match-end 4)
+			  '(org-protected t org-verbatim-emph t))
+     (goto-char (1+ (match-end 4))))))
 
 (defun org-export-protect-colon-examples ()
   "Protect lines starting with a colon."