Update class.osticket.php

IMPORTANT!!!!

On some configurations - like php running as fast cgi module - both statements returns true -         

isset($_SERVER['PATH_INFO'])
isset($_SERVER['ORIG_PATH_INFO'])

but only one of them is not equal to NULL.
Please note that this "issue" will affect upgrading or installation on new systems.

I would recommend to move away from using AcceptPathInfo. To normal requests with ? Because sometimes this directive hard to turn on.