Bump src/cloud_controller_ng

Bump cloudfoundry/cloud_controller_ng:
  Abhijit Hiremagalur:
     Merge remote-tracking branch 'origin/pr/153' ( Travis created: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/19370327 )
  fraenkel:
     Return 204 (NO CONTENT) instead of 409 (CONFLICT) when the same build pack bits are uploaded.  Its not an error but an optimization that is OK. ( Travis Unknown )

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