Fix renumbering for footnotes at BOL.

Hi all,

org-footnote-renumber-fn:N invalidates footnotes that appear as the
first thing on a line.  Here's a test file including the recipe.

--8<---------------cut here---------------start------------->8---
* Bla

  This is a line in which the following footnote that is inserted exactly
  [fn:1] is the first thing in that line.  And now invoke
  org-footnote-renumber-fn:N and see it breaking.

* Footnotes

[fn:1] Test
--8<---------------cut here---------------end--------------->8---

Note, that in larger org files, it's likely that you don't even notice
that the footnotes break.

Once I added a patch on patchwork that fixed this issue, and that's
shown as "accepted".

  http://patchwork.newartisans.com/patch/705/

I think, I've marked it as deferred or so myself because I've thought
the issue was fixed in the meantime, but that doesn't seem to be true.

Here's an updated patch.

lisp/org-footnote.el

@@ -895,16 +895,12 @@ If LABEL is non-nil, delete that footnote instead."
 	(goto-char (point-min))
 	(while (re-search-forward "\\[fn:\\([0-9]+\\)[]:]" nil t)
 	  (setq i (string-to-number (match-string 1)))
-	  (when (and (string-match "\\S-" (buffer-substring
-					   (point-at-bol) (match-beginning 0)))
-		     (not (assq i map)))
+	  (when (not (assq i map))
 	    (push (cons i (number-to-string (incf n))) map)))
 	(goto-char (point-min))
 	(while (re-search-forward "\\(\\[fn:\\)\\([0-9]+\\)\\([]:]\\)" nil t)
-	  (replace-match (concat "\\1"
-				 (cdr (assq (string-to-number (match-string 2))
-					    map))
-				 "\\3")))))))
+	  (setq i (cdr (assq (string-to-number (match-string 2)) map)))
+	  (replace-match (concat "\\1" i "\\3")))))))
 
 (defun org-footnote-auto-adjust-maybe ()
   "Renumber and/or sort footnotes according to user settings."