Illumos 1502 Remove conversion cruft from manpages

Reviewed by: Alexander Eremin <alexander.eremin@nexenta.com>
Reviewed by: Gordon Ross <gordon.w.ross@gmail.com>
Reviewed by: Garrett D'Amore <garrett.damore@gmail.com>

References:
https://www.illumos.org/issues/1502

Ported-by: Richard Laager <rlaager@wiktel.com>
Signed-off-by: Richard Laager <rlaager@wiktel.com>

Conflicts:
man/man8/zpool.8