firewalllogcountry.dat: Do not show 'Details' button for unkonw location.

firewalllogcountry.dat: Do not show 'Details' button for unkonw location.

The CGI offers the posibility to get more details for a certain locations
by clicking on a button.

This feature cannot be used for the category "unknown". To prevent users
from beeing confused about non show-able details, I added some code to hide
this button for this category.

Fixes #10726.

Signed-off-by: Stefan Schantl <stefan.schantl@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>