Set write_verify cbks in write_verify_init
Set write_verify cbks in write_verify_init

Set the cbk for write verify in write_verify_init so setup is done in
one place.

Signed-off-by: Mike Christie <39daeb1549a929782e38aa87c4e3da7f3844b09a@redhat.com>

open-iscsi/tcmu-runner,agrover/tcmu-runner,open-iscsi/tcmu-runner