Merge pull request #621 from CatoTH/Issue615

sortable and disableSelection are not always defined; lead to issue #615

openslides/agenda/static/javascript/agenda.js

@@ -76,8 +76,10 @@ $(function() {
         //# $('#hide_closed_items').attr('checked', true);
     //# }
 
+    if ($('#list_of_speakers').length > 0) {
         $('#list_of_speakers').sortable({axis: "y", containment: "parent", update: function(event, ui) {
             $('#speaker_list_changed_form').show();
         }});
         $('#list_of_speakers').disableSelection();
+    }
 });