bug#22472: 25.0.50; org-mode: latex fragments can't be un-rendered after a revert

[Dima Kogan <dima@secretsauce.net>]

Hi. I'm using a recent emacs from git, and a mostly-recent org-mode from
debian (Debian version 8.3.2-1). There's a bug:

1. emacs -Q

2. open an org-mode buffer that contains a latex fragment, for instance
==========
123

$\sqrt x$

123
=========

3. C-c C-x C-l

   This renders the latex fragment to show the equation graphically. It
   also tells the user (in the mini-buffer) that C-c C-c will remove the
   rendering, and go back to text

4. M-x revert-buffer

   At this point I would expect the render to revert to text, but it
   doesn't. This isn't necessarily a bug. However...

5. C-c C-c

   Here I ask emacs to un-render the fragment, but it does nothing. If
   #4 isn't a bug, then this is definitely a bug.

Thanks!