This PR is to ensure that we call the relevant object
layer APIs for necessary S3 API level functionalities
allowing gateway implementations to return proper
errors as NotImplemented{}
This allows for all our tests in mint to behave
appropriately and can be handled appropriately as
well.
To conform with AWS S3 Spec on ETag for SSE-S3 encrypted objects,
encrypt client sent MD5Sum and store it on backend as ETag.Extend
this behavior to SSE-C encrypted objects.
Removing an empty directory is not working because of xl.DeleteObject()
was only checking if the passed prefix is an actual object but it
should also check if it is an empty directory.