Call cache example no longer works

[Jarmo Hurri <jarmo.hurri@syk.fi>]

Greetings.

While trying to cache the results of a #+call, I found the following
example posted to this newsgroup in August 2012:

# ------------------------------------------------------------------
#+name: foo
#+begin_src emacs-lisp :var bar="baz"
  (sit-for 5)
  (message "bar=%S" bar)
#+end_src

#+RESULTS: foo
: bar="baz"

This does not return immediately, because the block must execute.
#+call: foo("quxxx")

#+RESULTS:
: bar="quxxx"

This returns immediately thanks to the cached result.
#+call: foo("qux") :cache yes
# ------------------------------------------------------------------

However, the last, cached call gives me an error with the latest
org-mode pulled and built 10 minutes ago:

mapconcat: Wrong type argument: listp, "results=foo(\"qux\")"

Unfortunately, due to tight work deadline, I have no time to start
debugging this but need to pass this on to you experts.

All the best,

Jarmo