Bump src/cloud_controller_ng

Bump cloudfoundry/cloud_controller_ng:
  Jeff Hui and Whitney Schaefer:
     Updated API version checksum. ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/42235520 )
     Added api documentation for service broker audit events. ( Travis Failed: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/42232639 )
     Added api documentation for service audit events. ( Travis Failed: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/42231022 )
     Added audit event when deleting a service via catalog sync ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/42226409 )
     Added audit event for updating services via catalog sync. ( Travis Unknown )
  Jeff Hui:
     Create service audit event when creating service when syncing from the catalog. ( Travis Unknown )