title: .sparkstaging directory in hdfs is not deleted
body: <p>We are running certain spark jobs and we see .sparkstaging directoring in hdfs persisting after the job completion.
  Is there any parameter we need to set to delete the staging directory after job completion?</p>
  
  <p>spark.yarn.preserve.staging.files is false by default and hence we have not set it explicitly.
  we are running spark on yarn using hortonworks and spark version 1.2</p>
  
  <p>Regards,
  Manju</p>