allow empty servers (Fixes: #3874)

Florian Schaal

2016-05-04 cc08f2c13f7155d6f3fb11afa7661aaec676858a

 interface/web/admin/lib/lang/cz_server.lng

@@ -12,6 +12,5 @@
$wb['- None -'] = '- Žádný -';
$wb['proxy_server_txt'] = 'Proxy-Server';
$wb['firewall_server_txt'] = 'Firewall-Server';
$wb['xmpp_server_txt'] = 'XMPP Server';
?>