OK, this GRE crap ain't working. Let's give up! Instead let's
have one tap-capable host per openQA deployment, so all the
tap jobs will go to it. This...should achieve that. Let's see
what blows up.
This adds openQA server, worker and dispatcher roles, and
applies them to the appropriate hosts. A few secret vars are
required. See trac #4958 for discussion.