Release the reference to the peripheral if returning a error.

That reference is to be held only if daopen() has been successful
and until daclose() releases it.  daclose() won't be called if
daopen() has failed, though.

Approved by:	re, njl
MFC after:	1 week

sys/cam/scsi/scsi_da.c

@@ -611,6 +611,8 @@ daopen(dev_t dev, int flags __unused, int fmt __unused, struct thread *td __unus
 	if (error == 0) {
 		if ((softc->flags & DA_FLAG_PACK_REMOVABLE) != 0)
 			daprevent(periph, PR_PREVENT);
+	} else {
+		cam_periph_release(periph);
 	}
 	cam_periph_unlock(periph);
 	return (error);