Allow '..' segment in photo/album paths through file_proxy (as is not…

… forbidden in other places like add album/item) and explitely look for /../ instead

Note: directory path can't end in '.' forcibly so this shall be fine
Fixes Ticket #1518

modules/gallery/controllers/file_proxy.php

@@ -45,7 +45,7 @@ public function __call($function, $args) {
     $file_uri = substr($request_uri, strlen($var_uri));
 
     // Make sure that we don't leave the var dir
-    if (strpos($file_uri, "..") !== false) {
+    if (strpos($file_uri, "/../") !== false) {
       throw new Kohana_404_Exception();
     }