Fixes a bug on AuthComponent syntax difference between CakePHP < 2.1 and >= 2.1.
Removed version_compare as CakePHP 2.0 AuthComponent works just fine with allow() [Thanks @ceeram]

Ref.:
https://github.com/cakephp/cakephp/blob/2.0.0/lib/Cake/Controller/Compon
ent/AuthComponent.php#L431