fix #1502 avoid duplicate entry and store pocket url in config

src/Wallabag/ImportBundle/DependencyInjection/WallabagImportExtension.php

@@ -13,6 +13,7 @@ class WallabagImportExtension extends Extension
     {
         $configuration = new Configuration();
         $config = $this->processConfiguration($configuration, $configs);
+        $container->setParameter('wallabag_import.pocket', $config['importers']['pocket_urls']);
 
         $loader = new Loader\YamlFileLoader($container, new FileLocator(__DIR__.'/../Resources/config'));
         $loader->load('services.yml');