When a virtual scsi DVD device is present with no image file
attached the storvsc driver logs all resulting unnecessary sense errors
whenever IO is issued to the device.

[storvsc] Sense Key : Not Ready [current]
[storvsc] Add. Sense: Medium not present - tray closed

[mkp: Fixed whitespace]
Signed-off-by: NCathy Avery <cavery@redhat.com>
Reviewed-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>