man: Remove obsolete info from hosts man page

The NIC no longer provides a host database, and hasn't for quite some
time. Remove that paragraph, it's not been relevant for many years. Also, hosts
appeared in 4.1c, not 4.2, so correct that too.

Noticed by: Henry Bent

(cherry picked from commit c22076b5283970908e74b3abece53efc4670e87d)