Bump src/cloud_controller_ng

Bump cloudfoundry/cloud_controller_ng:
  Eric Malm and Luan Santos:
     Change Gemfile to use github: for the github hosted gems ( Travis started: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/37643206 )
  Luan Santos and Mike Dalessio:
     Downgrade pg and newrelic_rpm ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/37620023 )