Bump src/cloud_controller_ng

Bump cloudfoundry/cloud_controller_ng:
  Chris Piraino and Rick Reilly:
     Bump API Version to 2.16.0 ( Travis created: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/38662058 )
     Bump vcap_common to 4.0.2. ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/38657438 )