Bump src/cloud_controller_ng

Bump cloudfoundry/cloud_controller_ng:
  Zach Robinson:
     Expose instance information from diego. ( Travis created: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/26895049 )
     Refactor stubbed instances_reporter expectations ( Travis Unknown )
     Refactor space summary controller. ( Travis Unknown )
  Onsi Fakhouri:
     Revert "Revert recent commits to fix CI" ( Travis Unknown )
  Derek Richard:
     Merge cc_api_docs and update API checksum ( Travis started: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/26892666 )
     Mark deprecated fields for service endpoints in api docs ( Travis started: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/26883783 )
     Add POST documentation for user_provided_service_instances ( Travis Unknown )
  Abhijit Hiremagalur:
     Rename and move abstract controllers ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/26877581 )
  David Sabeti and Derek Richard:
     Add service_plan_visibilities_api_spec ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/26871194 )
     Backfill service_bindings_api_spec ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/26810054 )
     Clean up service_instances_api_spec.rb ( Travis Unknown )
     Make validate_app and validate_service_instance private methods ( Travis Unknown )
     Backfill docs for /v2/service_instances [finishes #62359354] ( Travis finished: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/26803411 )
     Deprecate service_auth_tokens endpoint [finishes #64427434] ( Travis Unknown )
     /v2/service_brokers returns pretty output ( Travis Unknown )

Signed-off-by: Momchil Atanasov <m.momchil@gmail.com>