Different gateway implementations due to different backend
API errors, might return different unsupported errors at
our handler layer. Current code posed a problem for us because
this information was lost and we would convert it to InternalError
in this situation all S3 clients end up retrying the request.
To avoid this unexpected situation implement a way to support
this cleanly such that the underlying information is not lost
which is returned by gateway.
The new call combines GetObjectInfo and GetObject, and returns an
object with a ReadCloser interface.
Also adds a number of end-to-end encryption tests at the handler
level.
startOffset was re-assigned to '0' so it would end up
copying wrong content ignoring the requested startOffset.
This also fixes the corruption issue we observed while
using docker registry.
Fixes https://github.com/docker/distribution/issues/2205
Also fixes#3842 - incorrect routing.
