[SCSI] libosd: osd_dev_is_ver1 - Minor API cleanup

define a new osd_dev_is_ver1 that operates on devices
and the old osd_req_is_ver1 uses that new API.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>