Make set-visited-file-name reload local variables if needed.

* lisp/files.el (set-visited-file-name):
If the major-mode changed, reload the local variables.

Fixes: debbugs:9796

lisp/ChangeLog

+2011-10-27  Glenn Morris  <rgm@gnu.org>
+
+	* files.el (set-visited-file-name): If the major-mode changed,
+	reload the local variables.  (Bug#9796)
+
 2011-10-27  Chong Yidong  <cyd@gnu.org>
 
 	* subr.el (change-major-mode-after-body-hook): New hook.

lisp/files.el

@@ -3682,7 +3682,11 @@ the old visited file has been renamed to the new name FILENAME."
 	  (get major-mode 'mode-class)
 	  ;; Don't change the mode if the local variable list specifies it.
 	  (hack-local-variables t)
-	  (set-auto-mode t))
+	  ;; TODO consider making normal-mode handle this case.
+	  (let ((old major-mode))
+	    (set-auto-mode t)
+	    (or (eq old major-mode)
+		(hack-local-variables))))
     (error nil)))
 
 (defun write-file (filename &optional confirm)