devices and 500's

I really wanted to get something in there to simulate a tar-pitting device

I think I'd actually like to get a bit more flexible where you can have a large percentage of requests to a drive be varying degrees of terrible (i.e. taking 2-12 seconds to respond 100-continue, waiting 5-60 seconds before giving up a 200 after the last byte, or just being randomly slow reading and writing).

The 5XX stuff i just hacked in while I was working on https://review.openstack.org/135167

I'm sorta keen on seeing something like this added to the standard dev/review setup, so if you're not to busy with hummingbird and interested in taking patches upstream, I'll probably bake it into https://github.com/swiftstack/vagrant-swift-all-in-one