This commit adds support for SSE-KMS bucket configurations.
Before, the MinIO server did not support SSE-KMS, and therefore,
it was not possible to specify an SSE-KMS bucket config.
Now, this is possible. For example:
```
mc encrypt set sse-kms some-key <alias>/my-bucket
```
Further, this commit fixes an issue caused by not supporting
SSE-KMS bucket configuration and switching to SSE-KMS as default
SSE method.
Before, the server just checked whether an SSE bucket config was
present (not which type of SSE config) and applied the default
SSE method (which was switched from SSE-S3 to SSE-KMS).
This caused objects to get encrypted with SSE-KMS even though a
SSE-S3 bucket config was present.
This issue is fixed as a side-effect of this commit.
Signed-off-by: Andreas Auernhammer <aead@mail.de>
a1f70b106f