swift/test/s3api at 7bf279779995be5081e3ff9da7e113f20efe4446 - swift - OpenDev: Free Software Needs Free Tools

- SHA256 mismatches should trip XAmzContentSHA256Mismatch errors,
 not BadDigest. This should include ClientComputedContentSHA256 and
 S3ComputedContentSHA256 elements.
- BadDigest responses should include ExpectedDigest elements.
- Fix a typo in InvalidDigest error message.
- Requests with a v4 authorization header require a sha256 header,
 rejecting with InvalidRequest on failure (and pretty darn early!).
- Requests with a v4 authorization header perform a
 looks-like-a-valid-sha256 check, rejecting with InvalidArgument
 on failure.
- Invalid SHA256 should take precedence over invalid MD5.
- v2-signed requests can still raise XAmzContentSHA256Mismatch errors
 (though they *don't* do the looks-like-a-valid-sha256 check).
- If provided, SHA256 should be used in calculating canonical request
 for v4 pre-signed URLs.
Change-Id: I06c2a16126886bab8807d704294b9809844be086