Bug: relative link should be absolute

[clarknova]

pfsense version: 1.2.3RC1

Steps to recreate

1. Navigate to a page on pfsense that is not in the web root. i.e.,
http://192.168.2.1/packages/freeswitch/freeswitch_dialplan_includes.php

2. Click on the Firewall>Traffic_Shaper link

What happens:
404 error. Location bar reads "http://pfsense/packages/freeswitch/firewall_shaper.php"

What should happen:
Traffic Shaper page. Location bar reads " http://pfsense/firewall_shaper.php

[cmb]

This was changed in the base system because it wouldn't work through reverse proxies with absolute paths, and there are people who manage multiple devices that way. I don't know there is a good solution aside from breaking that ability again.