enable UNMAP when LUN is thin provisioned

- support Block Limits VPD page (0xB0)
 - add UNMAP to REPORT SUPPORTED OPERATION CODES
 - READ CAPACITY(16): set LBPME when Thin provisioning is enabled
 - move Thinprovisioning and BlockShift to config
 - add Unmap to BackingStore

pkg/scsi/scsilumap.go

@@ -73,7 +73,7 @@ func InitSCSILUMap(config *config.Config) error {
 	defer globalSCSILUMap.mutex.Unlock()
 
 	for _, bs := range config.Storages {
-		lu, err := NewSCSILu(bs.DeviceID, bs.Path, bs.Online)
+		lu, err := NewSCSILu(&bs)
 		if err != nil {
 			return fmt.Errorf("Init SCSI LU map error: %v", err)
 		}