update bunny to 1.1.0-release

Otherwise the following happens to rabbitmq watchers:

[2014-01-22T20:19:46.313550 #29832]  INFO -- Nerve::ServiceCheck::RabbitMQServiceCheck: nerve: service check rabbitmq rabbitmq-i-9334a2e3:40050 got error #<NoMethodError: undefined method `event_loop' for #<Bunny::Session:0x00000003469238>>
Merge pull request #38 from memory/bunny-upgrade

update bunny to 1.1.0-release