Fix drive rotational calculation status
If a MinIO drive path is mounted to a partition and not a real disk,
getting the rotational status would fail because Linux does not expose
that status to partition; In other words,
/sys/block/drive-partition-name/queue/rotational does not exist;
To fix the issue, the code will search for the rotational status of the
disk that hosts the partition, and this can be calculated from the
real path of /sys/class/block/<drive-partition-name>
b9269151a4