WebUI: DNS: remove --class option

Ticket: https://fedorahosted.org/freeipa/ticket/3414
Reviewed-By: Petr Vobornik <pvoborni@redhat.com>
Reviewed-By: Petr Spacek <pspacek@redhat.com>

install/ui/src/freeipa/dns.js

@@ -150,13 +150,6 @@ return {
                     'idnssoaexpire',
                     'idnssoaminimum',
                     'dnsttl',
-                    {
-                        $type: 'combobox',
-                        name: 'dnsclass',
-                        options: [
-                            'IN', 'CS', 'CH', 'HS'
-                        ]
-                    },
                     {
                         $type: 'radio',
                         name: 'idnsallowdynupdate',