[DoctrineMongoDBBundle] Fixed typo

src/Symfony/Bundle/DoctrineMongoDBBundle/DependencyInjection/DoctrineMongoDBExtension.php

@@ -114,7 +114,7 @@ class DoctrineMongoDBExtension extends Extension
     {
         $defaultDocumentManager = $container->getParameter('doctrine.odm.mongodb.default_document_manager');
         $defaultDatabase = isset($documentManager['default_database']) ? $documentManager['default_database'] : $container->getParameter('doctrine.odm.mongodb.default_database');
-        $proxyCacheDir = $this->container->getParameter('kernel.cache_dir').'/doctrine/odm/mongodb/Proxies';
+        $proxyCacheDir = $container->getParameter('kernel.cache_dir').'/doctrine/odm/mongodb/Proxies';
 
         $odmConfigDef = new Definition('%doctrine.odm.mongodb.configuration_class%');
         $container->setDefinition(sprintf('doctrine.odm.mongodb.%s_configuration', $documentManager['name']), $odmConfigDef);
@@ -380,4 +380,4 @@ class DoctrineMongoDBExtension extends Extension
     {
         return 'doctrine_odm';
     }
-}
+}