Fix the tests

@liveh2o @localshred 
@tamird here's what we do. Add `exit 0` to the end of `bin/rpc_server` but pitch it to the broader community as a "best practice." Nobody needs to know it actually solves a real issue a user was having. I mean, adding an explicit return code at the end of a script won't cause too much of a ruckus, will it? I definitely don't want to be flinging FUD about, but I think we can pull this off without anyone being the wiser. Our little secret. :speak_no_evil: :wink: