dansguardian: update to latest version 2.12.0.3

What little maintenance is being done on dansguardian looks to be on the 2.12 series these days. We needed the adjustable timeouts, and in fact extend the limits a bit (due to a 3 min 30 s POST request response time in a production system).

Compiles and runs on centos5 and centos6. Lightly tested.