Bump src/cloud_controller_ng

* Non-outside-facing cc changes.

Bump cloudfoundry/cloud_controller_ng:
  James Myers:
     To String on `user_guid` ( Travis created: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/23062850 )
     Extra logging for a flaky test ( Travis Failed: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/23059552 )

Signed-off-by: James Myers <jmyers@pivotallabs.com>