Bump src/cloud_controller_ng

Bump cloudfoundry/cloud_controller_ng:
  Eric Malm and Graeme Davison:
     Add additional tests for security group defaults ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/29639288 )
  Joseph Palermo:
     Clean up controller specs ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/29631246 )
Bump src/cloud_controller_ng

Bump cloudfoundry/cloud_controller_ng:
  Eric Malm and Graeme Davison:
     Bump API version to 2.8.0 ( Travis created: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/29643626 )