haproxy: Simplify haproxy configuration
haproxy: Simplify haproxy configuration

When I tested it locally, HAProxy was failing with a 503 error.  I
didn't really understand the config file, so I replaced it with
something much simpler taken from the HAProxy documentation.  This
happened to fix the error I was running into, so I figured we may as
well make it the default.

tejasmanohar/quilt,LuiseV/quilt,PenguinToast/quilt,kklin/kelda,kklin/quilt,stevenlin598/quilt,stevenlin598/quilt,kelda/kelda,tejasmanohar/quilt,stevenlin598/quilt,LuiseV/quilt,tejasmanohar/quilt,stevenlin598/quilt,kklin/quilt,NetSys/quilt,mmussomele/quilt,kayousterhout/quilt,kelda/kelda,mmussomele/quilt,quilt/quilt,stevenlin598/quilt,LuiseV/quilt,kayousterhout/quilt,kelda/kelda,NetSys/quilt,stevenlin598/quilt,ejj/quilt-dev,kayousterhout/quilt,NetSys/quilt,PenguinToast/quilt,NetSys/quilt,kklin/kelda,mmussomele/quilt,ejj/quilt-dev,kklin/quilt,PenguinToast/quilt,kklin/quilt,kayousterhout/quilt,PenguinToast/quilt,quilt/quilt,mmussomele/quilt,LuiseV/quilt,mmussomele/quilt,kklin/kelda,quilt/quilt,kelda/kelda,PenguinToast/quilt,tejasmanohar/quilt,LuiseV/quilt,ejj/quilt-dev,ejj/quilt-dev,mmussomele/quilt,kklin/kelda,quilt/quilt,NetSys/quilt