Merge branch 'release-4.1'

module/VuFind/src/VuFind/Session/Memcache.php

@@ -86,7 +86,8 @@ class Memcache extends AbstractBase
      */
     public function read($sess_id)
     {
-        return $this->getConnection()->get("vufind_sessions/{$sess_id}");
+        $value = $this->getConnection()->get("vufind_sessions/{$sess_id}");
+        return empty($value) ? '' : $value;
     }
 
     /**