Bump src/cloud_controller_ng

Bump cloudfoundry/cloud_controller_ng:
  Tammer Saleh:
     Further clean up ErrorHasher ( Travis created: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/19771198 )
     Use whitelist instead of blacklist for exposing error information through the API ( Travis created: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/19770477 )
     Refactor ErrorHasher ( Travis Unknown )
     Refactor ErrorHasher specs ( Travis Unknown )
     Remove unecessary logging statement ( Travis Unknown )

Signed-off-by: Ruth Byers <rbyers@pivotallabs.com>