symbol.c (restore_old_symbol): Fix thinko.

fortran/
	* symbol.c (restore_old_symbol): Fix thinko.

From-SVN: r196413

gcc/fortran/ChangeLog

 2013-03-03  Mikael Morin  <mikael@gcc.gnu.org>
 
+	* symbol.c (restore_old_symbol): Fix thinko.
+
+2013-03-03  Mikael Morin  <mikael@gcc.gnu.org>
+
 	* symbol.c (gfc_undo_symbols): Move code...
 	(restore_old_symbol): ... here as a new function.
 

gcc/fortran/symbol.c

@@ -2896,7 +2896,8 @@ restore_old_symbol (gfc_symbol *p)
 
   if (p->value != old->value)
     {
-      gfc_free_expr (old->value);
+      gcc_checking_assert (old->value == NULL);
+      gfc_free_expr (p->value);
       p->value = NULL;
     }