Update the source so the third party code passes the File Structure Test

modules/gallery/lib/HTMLPurifier/HTMLPurifier.path.php

@@ -0,0 +1,11 @@
+<?php defined("SYSPATH") or die("No direct script access.");
+
+/**
+ * @file
+ * Convenience stub file that adds HTML Purifier's library file to the path
+ * without any other side-effects.
+ */
+
+set_include_path(dirname(__FILE__) . PATH_SEPARATOR . get_include_path() );
+
+// vim: et sw=4 sts=4