org-id.el: Don't set `kill-emacs-hook' on noninteractive sessions.

Upstream change from Juanma Barranquero <lekktu@gmail.com>
See message on Sun, 06 Mar 2011 01:30:16 on emacs-diff:

  [Emacs-diffs] /srv/bzr/emacs/trunk r103541: * lisp/bookmark.el:

lisp/org-id.el

@@ -519,7 +519,8 @@ When CHECK is given, prepare detailed information about duplicate IDs."
     (puthash id (abbreviate-file-name file) org-id-locations)
     (add-to-list 'org-id-files (abbreviate-file-name file))))
 
-(add-hook 'kill-emacs-hook 'org-id-locations-save)
+(unless noninteractive
+  (add-hook 'kill-emacs-hook 'org-id-locations-save))
 
 (defun org-id-hash-to-alist (hash)
   "Turn an org-id hash into an alist, so that it can be written to a file."