call to user_save() in guestbook_page() wrongly over-writes global user object

In guestbook_page() (in guestbook.module), there is a call to user_save() in which the global $user object is passed. In my case, the $user->roles was getting modified for the rest of the page execution. This was bad, because blocks whose access to users depended on those roles were disappearing. I don't know if you're still accepting patches for the DRUPAL-5--2 branch, but I've attached a patch that changes to code to accomplish the same thing intended by the mentioned user_save() call (which was to record the most recent time that a user sees his/her own guestbook) and record it to the database.