joomla/joomla-platform — pull request #1794 by florianv (2013-01-10 10:53:13+00:00)
Title: Avoid include_once when we are sure the class doesn't exist

Since a class_exists call was added in all loadByNamespace methods, include_once is no more needed.

APC also prefers include :
http://php.net/manual/en/apc.configuration.php#ini.apc.include-once-override