Use a custom tmp directory

.gitignore

 vagrant/dev/.vagrant
 data
-
+tmp

plugins/cas_auth_unl/start.php

@@ -142,7 +142,7 @@ class UnlCAS {
         $driver = new Stash\Driver\FileSystem();
 
         // Setting a custom path is done by passing an options array to the constructor.
-        $options = array('path' => sys_get_temp_dir() .'/elgg_session_map_' . md5(__DIR__));
+        $options = array('path' => __DIR__ .'/../../tmp/elgg_session_map');
         $driver->setOptions($options);
 
         $pool = new Stash\Pool($driver);