Restore adminmessages in notification type dropdown

Signed-off-by: Richard Mansfield <richardm@catalyst.net.nz>

htdocs/account/activity/index.php

@@ -46,6 +46,10 @@ $types = array_map(create_function('$a', '
     return get_string("type" . $a->name, $section);
     '), $types);
 
+if ($USER->get('admin')) {
+    $types['adminmessages'] = get_string('typeadminmessages', 'activity');
+}
+
 $type = param_alphanum('type', 'all');
 if (!isset($types[$type])) {
     $type = 'all';