title: S3A: fails while S3: works in Spark EMR
body: <p>I'm using EMR 5.5.0 with Spark.  If I write a simple file to s3 using an <code>s3://...</code> URL it writes fine.  But if I use an <code>s3a://...</code> address, it fails with <code>Service: Amazon S3; Status Code: 403; Error Code: AccessDenied</code></p>
  
  <p>Using the AWS command line I'm able to cp, mv, and rm any file in the path I'm writing to.  But from spark, <code>s3a</code> fails on the put command.  </p>
  
  <p>We have Server Side Encryption Enabled, and I know spark knows because the <code>s3</code> URLs work.  Any ideas? </p>
  
  <p>Failed PUT DEBUG logs <a href="https://pastebin.com/B6KU5nPu" rel="noreferrer">here</a>.  Maybe its important to note, I'm doing an <code>rdd.saveAsTextFile(path)</code> but the put command says its trying to write to <code>/my-bucket/tmp/carlos/testWrite/4/_temporary/0/</code> which it should only do in parquet?  Not sure if that detail is relevant but thought I would mention.</p>