Fix PERSISTENT RESERVE IN / READ RESERVATION response unmarshalling

The code that verifies the pr_type response must compare only the
lower four bits of byte 21 of the response ("TYPE") and must ignore
the upper four bits ("SCOPE").

Signed-off-by: Bart Van Assche <bvanassche@acm.org>

include/scsi-lowlevel.h

@@ -803,6 +803,7 @@ struct scsi_persistent_reserve_in_read_reservation {
        int reserved;
 
        uint64_t reservation_key;
+       unsigned char pr_scope;
        unsigned char pr_type;
 };