verify: treat as failure if given verify type is different from media

verify: treat as failure if given verify type is different from media

When fio verifies right now, it'll look at the on media stored type
and verify that type. This means that if verify=foo set and we
find older blocks that are written with verify=bar, we will
verify those against bar.

Change this so that if a specific verify type is given, that type
is ALWAYS used for verification. If none is given but asked to
verify, we retain the old behaviour of just verifying based on
the type given in the on-media block.

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