chat: harden check for kick messages

panikweb_templates/static/js/specifics.js

@@ -622,6 +622,8 @@ $(function() {
                                             var nick = $('.nick input').val()
                                             var muc = $('div#chat').data('chatroom');
                                             if (pres.getElementsByTagName('status').length == 1 &&
+                                                pres.getElementsByTagName('status')[0].attributes &&
+                                                pres.getElementsByTagName('status')[0].attributes.code &&
                                                 pres.getElementsByTagName('status')[0].attributes.code.value == '307') {
                                               /* kicked */
                                               var kicked = pres.getElementsByTagName('item')[0].attributes.nick.value;