bug#24149: 25.1; set-transient-map bug

[Leo Liu]

1. Enable temp-buffer-browse-mode
2. (cl-loop repeat 2 do (with-output-to-temp-buffer "*test*" (princ "ok")))
3. Check pre-command-hook

#:clear-transient-map will be there forever.

The issue is caused by two identical calls of set-transient-map that
share the same keymap. so deactivation of the second call has an
side-effect on the first call.

Stefan, is the following the right fix?

Thanks,
Leo

diff --git a/lisp/subr.el b/lisp/subr.el
index 2c0be204..b6a38778 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -4542,7 +4542,8 @@ to deactivate this transient map, regardless of 
KEEP-PRED."
             (with-demoted-errors "set-transient-map PCH: %S"
               (unless (cond
                        ((null keep-pred) nil)
-                       ((not (eq map (cadr overriding-terminal-local-map)))
+                       ((and (keymapp (cadr overriding-terminal-local-map))
+                             (not (eq map (cadr 
overriding-terminal-local-map))))
                         ;; There's presumably some other transient-map in
                         ;; effect.  Wait for that one to terminate before we
                         ;; remove ourselves.