Description:
------------
The code inside the Controller class_exists ('db').
Will result in an error.
Warning: Yaf_Loader::autoload(): Failed opening script librarys/db.php: No such 
file or directory in /home/qiufeng/work/yaf/application/controllers/Index.php on 
line 5

Test script:
---------------
<?php
class IndexController extends Yaf_Controller_Abstract {
	public function indexAction() {
		class_exists('db');
	}
}
?>
//=======================
// output
Warning: Yaf_Loader::autoload(): Failed opening script librarys/db.php: No such file or directory in /home/qiufeng/work/yaf/application/controllers/Index.php on line 5

Expected result:
----------------
Does not affect its own function.