scsi: pass down REQUEST SENSE to the device when there is no stored sense This will let scsi-block/scsi-generic report progress on long operations. Reported-by: Thomas Schmitt <scdbackup@gmxbackup.net> Tested-by: Thomas Schmitt <scdbackup@gmxbackup.net> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>