virtio-blk: pass full status to the guest
When SCSI passthrough is being used by the guest with virtio-blk, the
guest is not able to detect disk failures. This is because the status
field is expected by the guest driver to include also the msg_status,
host_status and driver_status fields, but the device is only passing
down the SCSI status.
The patch fixes this, and also makes sure that the guest always sees a
CHECK_CONDITION status when there is valid sense data.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>