binding to hardcoded port 8545 fails when launching nodes on different ports

[nimakaviani]

Currently we have hardcoded port 8545 when trying to deploy the contract using pusher.js.

https://github.com/cloudfoundry-incubator/blockhead/blob/master/pkg/deployer/deployer.go#L52-L64

Port configuration should ideally come from whatever port that is specified in the json description of the service.

[nimakaviani]

fixed in this commit: 6672a54

Assumes the first port in the service specification to be the serving container port