Put the module_load_include() in hook_init().

Previously, the following call to module_load_include was sitting in the .module file without being contained in a function:

module_load_include('inc', 'auto_expire', 'auto_expire');

However, this generates a pile of PHP warnings since the autoexpire.inc file contains defines, and it gets included multiple times throughout the course of a pageload.

I've moved this module_load_include into a hook_init(), so that it is only called once per page request.