Deprecate verifysort and verifysort_nr

Deprecate verifysort and verifysort_nr

It was an optimization to read back verifies in a sorted order,
for rotational storage. But I don't think the option makes much
sense, and I've never heard of anyone using it. Mark it as
deprecated, and always verify in the same order that IO was
written.

Signed-off-by: Jens Axboe <axboe@kernel.dk>