multiple fixes - init script, passenger_stats, RMQ pubsub handler

Hello,

here are few fixes/mods to Diamond. Hopefully, I've described everything in commit messages, therefore it feels redundant do it again here.
One thing that's missing, though, is RMQ PubSub handler requires pika 0.9.13 now, although I don't remember (anymore) what change, resp. parameter enforces this requirement.

If you have any questions, please, let me know. Even if it should be ``describechanges in PR here''. ;)

Thanks!

PS: I'm sorry for previous PR. It was unwise to open in on master branch :-\ At least, I think so.