Update extrafields.class.php

The property $errno was declared of type integer, but $this->db->lasterrno() is of type string

htdocs/core/class/extrafields.class.php

@@ -148,7 +148,7 @@ class ExtraFields
 	public $errors = array();
 
     /**
-	 * @var integer DB Error number
+	 * @var string DB Error number
 	 */
 	public $errno;