bug #405 Fix the build (loic425)

This PR was merged into the 1.9-dev branch.

Discussion
----------

| Q               | A
| --------------- | -----
| Bug fix?        | yes (on test app)
| New feature?    | no
| BC breaks?      | no
| Deprecations?   | no
| Related tickets | 
| License         | MIT


Commits
-------

3d96a92 Fix logger

src/Bundle/test/config/services.yaml

@@ -11,7 +11,8 @@ parameters:
 services:
     # Gets rid of "[error] Uncaught PHP Exception Symfony\Component\HttpKernel\Exception\NotFoundHttpException"
     # errors in PHPUnit output when testing 404 errors.
-    logger: "@Psr\Log\NullLogger"
+    Psr\Log\NullLogger: ~
+    logger: '@Psr\Log\NullLogger'
 
     # Default configuration for services in *this* file
     _defaults: