S3 IO method: remove signature version 4 unit test; fix authorization version 4 put request by using sha256 instead of md5.
S3 IO method: remove signature version 4 unit test; fix authorization version 4 put request by using sha256 instead of md5.

quantcast/qfs,quantcast/qfs,quantcast/qfs,quantcast/qfs,quantcast/qfs,quantcast/qfs,quantcast/qfs,quantcast/qfs