target: Use TCM_NO_SENSE for initialisation

The compiler complained about uninitialized variables, so
use TCM_NO_SENSE here.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Cc: Nicholas Bellinger <nab@risingtidesystems.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>