Invert condition for configuring JMSDiExtraBundle

The Admin annotation was not picked up because JMSDiExtraBundle was configured when it is not present instead of when it is.

DependencyInjection/SonataAdminExtension.php

@@ -216,7 +216,7 @@ class SonataAdminExtension extends Extension implements PrependExtensionInterfac
     {
         $bundles = $container->getParameter('kernel.bundles');
 
-        if (!isset($bundles['JMSDiExtraBundle'])) {
+        if (isset($bundles['JMSDiExtraBundle'])) {
             $container->prependExtensionConfig(
                 'jms_di_extra',
                 array(