Merge pull request #1941 from jfefe/patch-3

Avoid missing class error for fetch_thirdparty method

htdocs/core/class/commonobject.class.php

@@ -579,6 +579,8 @@ abstract class CommonObject
         if (!class_exists('Societe'))
 	    require_once DOL_DOCUMENT_ROOT.'/societe/class/societe.class.php';
 
+	require_once DOL_DOCUMENT_ROOT.'/societe/class/societe.class.php';
+
         $thirdparty = new Societe($this->db);
         $result=$thirdparty->fetch($this->socid);
         $this->client = $thirdparty;  // deprecated