Edit source: fix 'end' initialisation

* org-src.el: Create a marker to pass to copy-marker.

This fixes a 'wrong type argument' error when running
org-edit-src-code (observed on Emacs 23.2.1).

The problem was that copy-marker expects a marker, and it was given
nil. This change gives it a marker that doesn't point anywhere, but
still lets us set the insertion type of the end marker.

TINYCHANGE

lisp/org-src.el

@@ -230,7 +230,7 @@ buffer."
 	 (beg (make-marker))
 	 ;; Move marker with inserted text for case when src block is
 	 ;; just one empty line, i.e. beg == end.
-	 (end (copy-marker nil t))
+	 (end (copy-marker (make-marker) t))
 	 (allow-write-back-p (null code))
 	 block-nindent total-nindent ovl lang lang-f single lfmt buffer msg
 	 begline markline markcol line col transmitted-variables)