verify: disable header seed checking instead of overwriting it

verify: disable header seed checking instead of overwriting it

The existing header seed is overwritten if zone reset frequency is set or
if verify backlog is enabled. Disable verify header seed check for these
scenarios, unless there is an explicit request to enable it.

Note: There is no fio behavior change intended by this patch.

Signed-off-by: Ankit Kumar <ankit.kumar@samsung.com>