nvmet: remove redundant assignments of variable status

There are two occurrances where variable status is being assigned a
value that is never read and it is being re-assigned a new value
almost immediately afterwards on an error exit path. The assignments
are redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>