Currently, the backend minio server uses the same data directory as the mint test itself, causing `s3 sync` to fail often. Now `minio` backend will use a different data directory `/data` instead of `/mint/data`
Currently, the backend minio server uses the same data directory as the mint test itself, causing `s3 sync` to fail often. Now `minio` backend will use a different data directory `/data` instead of `/mint/data`