(maint) Remove raring and quantal cows, as they are EOL

Ubuntu raring[1] and quantal[2] are EOL, so we should no longer be
building packages for them. This commit removes them from the build
defaults file.

[1] - http://fridge.ubuntu.com/2014/01/28/ubuntu-13-04-raring-ringtail-end-of-life-reached-on-january-27-2014/
[2] - http://fridge.ubuntu.com/2014/05/17/ubuntu-12-10-quantal-quetzal-end-of-life-reached-on-may-16-2014/