Write Zeroes sets PRACT when block integrity is enabled (as it should),
but neglects to also set the reftag which is expected by reads. This
causes protection errors on reads.

Fix this by setting the reftag for type 1 and 2 (for type 3, reads will
not check the reftag).

Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>