title: Symfony exception when registering new Doctrine event subscriber (SoftDeleteable)
body: <p>I'm using Symfony 2.3 with Sonata Admin Bundle with <a href="https://github.com/l3pp4rd/DoctrineExtensions" rel="nofollow">DoctrineExtensions</a> (which is enabled by <a href="https://github.com/stof/StofDoctrineExtensionsBundle" rel="nofollow">StofDoctrineExtensionsBundle</a>). I enabled, configured and successfully tested SoftDeleteable and Timestampable components.</p>
  
  <p>Now, when I try adding another Doctrine event subscriber using Symfony tagged service, it seems as the softdeleteable listener is being disabled.</p>
  
  <p>My service:
  </p>
  
  <pre><code>my.contact.listener.tag:
      class: My\ContactBundle\EventListener\TagListener
      tags:
          - { name: doctrine.event_subscriber, connection: default }
      calls:
          - [ setTagManager, [ @fpn_tag.tag_manager ] ]
  </code></pre>
  
  <p>Subscriber:
  </p>
  
  <pre><code>namespace My\ContactBundle\EventListener;
  
  
  use Doctrine\Common\EventSubscriber;
  use Doctrine\ORM\Event\LifecycleEventArgs;
  use DoctrineExtensions\Taggable\Taggable;
  use FPN\TagBundle\Entity\TagManager;
  
  class TagListener implements EventSubscriber
  {
      /**
       * @var TagManager
       */
      private $tagManager;
  
      /**
       * @param \FPN\TagBundle\Entity\TagManager $tagManager
       */
      public function setTagManager($tagManager)
      {
          $this-&gt;tagManager = $tagManager;
      }
  
      /**
       * Load tags for Taggable entities
       *
       * @param LifecycleEventArgs $args
       */
      public function postLoad(LifecycleEventArgs $args)
      {
          $entity = $args-&gt;getEntity();
  
          if ($entity instanceof Taggable) {
              $this-&gt;tagManager-&gt;loadTagging($entity);
          }
      }
  
      /**
       * Save tags for Taggable entities
       *
       * @param LifecycleEventArgs $args
       */
      public function preUpdate(LifecycleEventArgs $args)
      {
          $entity = $args-&gt;getEntity();
  
          if ($entity instanceof Taggable) {
              $this-&gt;tagManager-&gt;saveTagging($entity);
          }
      }
  
      /**
       * Save tags for Taggable entities
       *
       * @param LifecycleEventArgs $args
       */
      public function prePersist(LifecycleEventArgs $args)
      {
          $entity = $args-&gt;getEntity();
  
          if ($entity instanceof Taggable) {
              $this-&gt;tagManager-&gt;saveTagging($entity);
          }
      }
  
      public function getSubscribedEvents()
      {
          return array(
              'prePersist',
              'preUpdate',
              'postLoad',
          );
      }
  }
  </code></pre>
  
  <p>In each request I get exception:</p>
  
  <pre><code>Listener "SoftDeleteableListener" was not added to the EventManager!
  </code></pre>
  
  <p>If I disable my subscriber, the problem is gone. How to enable my event subscriber and have softdeleteable too?</p>