Avoid performing a type conversion

`object_id` is of type `varchar`, whereas the parameter is passed as an integer. This forces MySQL to perform a type conversion from integer to string which has a performance impact in the SQL query.

Author: loalf

lib/Gedmo/Loggable/Entity/Repository/LogEntryRepository.php

@@ -56,7 +56,7 @@ public function getLogEntriesQuery($entity)
         $dql .= " AND log.objectClass = :objectClass";
         $dql .= " ORDER BY log.version DESC";
 
-        $objectId = $wrapped->getIdentifier();
+        $objectId = (string) $wrapped->getIdentifier();
         $q = $this->_em->createQuery($dql);
         $q->setParameters(compact('objectId', 'objectClass'));