Adds a new option fs.s3a.create.storage.class which can
be used to set the storage class for files created in AWS S3.
Consult the documentation for details and instructions on how
disable the relevant tests when testing against third-party
stores.
Contributed by Monthon Klongklaew
Change-Id: I8cdebadf294a89fde08d98729ad96f251d58411c
7ec988d264