Bump src/cloud_controller_ng

Bump cloudfoundry/cloud_controller_ng:
  Ryan Tang:
     Print #inspect of request body instead of #to_s. ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/13714534 )
  alex choi:
     do not allow deletion if there are associated instances ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/13709606 )
  Maria Shaldibina:
     Re-enable deleting shared tests ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/13703238 )
  Dan Lavine:
     Added a regular expression to check for escape characters in object names. ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/13700037 )
  Alex Suraci:
     stop using standard_model_object ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/13666980 )
     exclude disabled buildpacks from staging message ( Travis Unknown )
     add 'enabled' flag to buildpacks ( Travis Unknown )
  Ruth Byers:
     Merge branch 'instances_error' of https://github.com/bravera/cloud_controller_ng ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/13663591 )
  Andy Bravery:
     Catch instances less than zero error ( Travis Unknown )