Update spec/test_cluster.rb to work with latest 0.8
Update spec/test_cluster.rb to work with latest 0.8

bpot/poseidon,airbnb/poseidon,Shopify/poseidon,chingor13/poseidon,SponsorPay/poseidon,gjackson12/poseidon,nepalez/poseidon,apptentive-engineering/poseidon,ListenFirstMedia/poseidon,Tapjoy/poseidon,codeclimate/poseidon