Make specs less timeout dependent

Got the specs running reliably now, but had to re add Adapter#shutdown.
Because of eventmachine the before and after blocks in adapter_lint.rb are a mess now,
would really appreciate it if someone can come up with a cleaner solution.
I only got to this now, and unfortunately don't have a lot of time because I'm packing my stuff for 2 weeks of holiday :)

The way it is right now, in this diff, the pipe doesn't really have any effect, because it fires right after constructing the adapter, while the work we're actually waiting for happens in Adapter#run.

When I added the sleep call that you killed here, I wasn't sure why it fixed the still-flakey spec suite, but in retrospect I guess the server thread sometimes didn't get any chance to run at all. So the sleep call is a lame substitute for Thread.pass :)

Could you instead try exchanging the sleep calls with just Thread.pass? Don't have the time right now to test it myself.