Bump src/cloud_controller_ng

Bump cloudfoundry/cloud_controller_ng:
  Ruth Byers:
     Updated specs to reflect default_app_memory=1024 ( Travis started: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/15376751 )
     Default app memory is configurable ( Travis Unknown )
  Phan Le:
     Use the correct version of ruby ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/15373875 )
     Remove domains_spaces table which is replaced by private/shared domains [finished #62406482] ( Travis Unknown )