Bump src/cloud_controller_ng

Bump cloudfoundry/cloud_controller_ng:
  James Myers:
     Merge branch master of https://github.com/cloudfoundry/cloud_controller_ng ( Travis created: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/27900542 )
     Merge remote-tracking branch origin/pr/222 ( Travis Unknown )
  Zach Robinson:
     Refactor BuildpackBitsDelete and Blobstore::Client.delete ( Travis Unknown )
     Add egress rules to staging and start messages to DEA ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/27891994 )
     Move undo_app_changes_spec to correct location ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/27886917 )
  Joseph Palermo:
     Fix flakey test assertion. Postgres ordering is not consistent. ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/27895219 )
     Remove obsolete api doc markdown ( Travis Unknown )
     Remove unused ResponseMessage objects ( Travis Unknown )
     Clean up api docs dsl to do validation against expected attributes ( Travis Success: https://travis-ci.org/cloudfoundry/cloud_controller_ng/builds/27892406 )
  fraenkel:
     Make sure we are going to delete the same blob that was requested some time in the past. ( Travis Unknown )

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