Fix for if there is no zoneinfo File, but the network table is loaded

This Fixes the issue: 
http://sickbeard.com/forums/viewtopic.php?f=13&t=2386&start=1860#p41008
https://github.com/mr-orange/Sick-Beard/commit/14a6d63f0195086839bc4efd11eed5216ac05de6