fix memory leak from not destroying the scheduler context on module unload

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.2@9609 65c4cc65-6c06-0410-ace0-fbb531ad65f3

pbx/pbx_dundi.c

@@ -4726,6 +4726,7 @@ int unload_module(void)
 	ast_unregister_switch(&dundi_switch);
 	ast_custom_function_unregister(&dundi_function);
 	res = ast_unregister_application(app);
+	sched_context_destroy(sched);
 	return res;
 }