[O] Temp files are not deleted after beamer export with source code blocks

[James Harkins]

I've set org-latex-listings to "Use listings" (not minted), and then run 
this minimal example.

~~~~
#+BIND: org-latex-listings-options (("basicstyle" "\\ttfamily") 
("captionpos" "b") ("tabsize" "3"))

#+LANGUAGE:  en
#+OPTIONS:   H:1 num:t toc:nil \n:nil @:t ::t |:t ^:t -:t f:t *:t <:t ':t
#+EXPORT_SELECT_TAGS: export
#+EXPORT_EXCLUDE_TAGS: noexport

#+startup: beamer
#+LaTeX_CLASS: beamer
#+LaTeX_CLASS_OPTIONS: [presentation]
#+BEAMER_THEME: default
#+COLUMNS: %45ITEM %10BEAMER_env(Env) %10BEAMER_act(Act) %4BEAMER_col(Col) 
%8BEAMER_opt(Opt)
#+PROPERTY: BEAMER_col_ALL 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0.0 :ETC

#+LATEX_HEADER: \usepackage{listings}

#+TITLE:     Test
#+AUTHOR:    hjh

* A frame
** You can write some code like this.
#+begin_src {} -i :exports code
some code here
#+end_src
~~~~

Now there is a file "beamer-listings-2.vrb" containing the LaTeX code for 
the second frame. This file never gets deleted. As I'm developing the 
presentation, chances are that frame will end up becoming a different frame 
number, so I keep getting more and more vrb files on disk.

Shouldn't org clean these up after LaTeX is finished? It already cleans up 
other temporary LaTeX files.

hjh