Contributed by Steve Loughran.
The S3Guard absence warning of HADOOP-16484 has been changed
so that by default the S3A connector only logs at debug
when the connection to the S3 Store does not have S3Guard
enabled.
The option to control this log level is now
fs.s3a.s3guard.disabled.warn.level
and can be one of: silent, inform, warn, fail.
On a failure, an ExitException is raised with exit code 49.
For details on this safety feature, consult the s3guard documentation.
93b662db47