[fix #49131067] upgraded bunny gem to 0.9.0.pre10

This bunny version introduces:
- More Reliable Heartbeat Sender
- Network Recovery After Delay
- Default Heartbeat Value Is Now Server-Defined
- Concurrency Improvements On JRuby
- Explicitly Closed Sockets
- Bunny::Exception Now Extends StandardError

http://blog.rubyrabbitmq.info/blog/2013/04/22/bunny-0-dot-9-0-dot-pre9-is-released/
http://blog.rubyrabbitmq.info/blog/2013/05/02/bunny-0-dot-9-0-dot-pre10-is-released/