Follow on to
* HADOOP-13887. Encrypt S3A data client-side with AWS SDK (S3-CSE)
* HADOOP-17817. S3A to raise IOE if both S3-CSE and S3Guard enabled
If the S3A bucket is set up to use S3-CSE encryption, all tests which turn
on S3Guard are skipped, so they don't raise any exceptions about
incompatible configurations.
Contributed by: Mehakmeet Singh