fix bug with Sonata :

Method Jm\ABBundle\Entity\Template::__toString() must return a string

Author: jeremymarc

Entity/Template.php

@@ -211,7 +211,7 @@ public function getUpdatedAt()
 
  public function __toString()
  {
- return $this->getName();
+ return $this->getName() ?: '';
  }
 
  /**