Fix argument to buffer-live-p in read-char-choice

lisp/ChangeLog

+2011-10-05  Leo Liu  <sdl.web@gmail.com>
+
+	* subr.el (read-char-choice): Fix argument to buffer-live-p which
+	works with buffer object.
+
 2011-10-05  Stefan Monnier  <monnier@iro.umontreal.ca>
 
 	* mpc.el (mpc-tool-bar-map): Add labels.

lisp/subr.el

@@ -2170,7 +2170,7 @@ keyboard-quit events while waiting for a valid input."
 	    (setq prompt (propertize prompt 'face 'minibuffer-prompt)))
 	  (setq char (let ((inhibit-quit inhibit-keyboard-quit))
 		       (read-key prompt)))
-	  (and show-help (buffer-live-p helpbuf)
+	  (and show-help (buffer-live-p (get-buffer helpbuf))
 	       (kill-buffer helpbuf))
 	  (cond
 	   ((not (numberp char)))