Fix zones for numjobs=x, where x > 1

Fix zones for numjobs=x, where x > 1

In the options fixup, we auto-set open_files to 1 if it hasn't been set.
So any duplicated jobs will clear the zone. Fixup the check to properly
check for > 1 open files.

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