Fix sort error for streams with names that are numeric

The jQuery .data() documentation says: "Every attempt is made to
convert the string to a JavaScript value (this includes booleans,
numbers, objects, arrays, and null) otherwise it is left as a
string. To retrieve the value's attribute as a string without any
attempt to convert it, use the attr() method."

(imported from commit f47c1cbb94cb5a98ea9842b00f45c35cd21873f9)

zephyr/static/js/ui.js

@@ -907,7 +907,7 @@ function sort_narrow_list() {
     var items = $('#stream_filters li').get();
     var parent = $('#stream_filters');
     items.sort(function(a,b){
-        return $(a).data('name').localeCompare($(b).data('name'));
+        return $(a).attr('data-name').localeCompare($(b).attr('data-name'));
     });
 
     parent.empty();