Variable: pcmpl-ssh-known-hosts-file

If non-nil, a string naming your SSH "known_hosts" file.
This allows one method of completion of SSH host names, the other
being via `pcmpl-ssh-config-file'. Note that newer versions of
ssh hash the hosts by default, to prevent Island-hopping SSH
attacks. This can be disabled, at some risk, with the SSH option
"HashKnownHosts no".