Hostname match minion id.

Enforces hostname matching minion id. You should check your minion ids match your hostname before applying! Especially if you have [RabbitMQ](http://stackoverflow.com/questions/14659335/rabbitmq-server-fails-to-start-after-hostname-has-changed-for-first-time) installed.
Yet another case where I'd like a state to force a refresh of grains half way through a minion. I wonder if that's possible to create........ :thought_balloon: