Fragment handler call set request instead of using listener

These 2 commits were made in fabpot/contagious-services which was in #7007. I think these changes need to be applied to the 2.2 branch as well since if they are not applied then you can not create a request in an event listener class and have fragments render from a view without getting the following error:

```Undefined offset: 0 in .../src/Symfony/Component/HttpKernel/Fragment/FragmentHandler.php```

Not sure if this pull request can be applied without 2ffcfb98c870f1d88fcfc1e403e56613400394a9 and ec1e7ca6ac7364efecf5cc1ac891089a6d38da49 but from my testing.