target/iblock: Fix double bioset_integrity_free bug

This patch fixes a double free bug during IBLOCK backend shutdown
where bioset_integrity_free() was incorrectly called ahead of
bioset_free(), who is already making the same call directly.

This bug was introduced with commit ecebbf6cc, and will end up
triggering a general protection fault in iblock_free_device()

Reviewed-by: Sagi Grimberg <[e-mail]>
Cc: Martin K. Petersen <[e-mail]>
Cc: Or Gerlitz <[e-mail]>
Cc: Quinn Tran <[e-mail]>
Cc: Giridhar Malavali <[e-mail]>
Cc: <[e-mail]> #3.14+
Signed-off-by: Nicholas Bellinger <[e-mail]>

drivers/target/target_core_iblock.c

···
 
 	if (ib_dev->ibd_bd != NULL)
 		blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
-	if (ib_dev->ibd_bio_set != NULL) {
-		bioset_integrity_free(ib_dev->ibd_bio_set);
+	if (ib_dev->ibd_bio_set != NULL)
 		bioset_free(ib_dev->ibd_bio_set);
-	}
+
 	kfree(ib_dev);
 }