Unless I'm missing something, it seems mildly preferable to instead use *SAVE-HOOKS* to get the *LOG-OUTPUT* to NIL.
Not that it's a huge difference in practice -- just tidier to clean up the old stream before saving.
any chance for a fix? it keeps popping up on #lisp...
currently i have a kludge to 'fix' it:
#+sbcl (push (lambda () (setf swank::*log-output* nil)) sb-ext:*save-hooks*)
the proper fix depends on the maintainers' taste.