Bump src/cloud_controller_ng

Bump cloudfoundry/cloud_controller_ng:
  Abhijit Hiremagalur:
     Reintroduce parallelism to avoid Travis timeouts ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/26322308 )
  James Myers:
     Remove non_transactional flag from service broker specs ( Travis finished: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/26257512 )
  Michael Fraenkel:
     Reseed stacks when resetting the database in test ( Travis Unknown )
     Remove non_transactional flag from UsageEvent repo specs ( Travis Unknown )