man: minor fixes for sections before "JOB PARAMETERS" for consistency

man: minor fixes for sections before "JOB PARAMETERS" for consistency

This is the continuation of below series of patches as well as the
previous 2 commits to sync the man page with HOWTO.

[PATCH 0/7] Sync fio(1) man page with HOWTO
http://www.spinics.net/lists/fio/msg06008.html

This commit consists of minor fixes to sync formats in the earlier
sections (made by above series of pathches) with the previous 2 commits.
The contents remain the same.

Signed-off-by: Tomohiro Kusumi <tkusumi@tuxera.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>