bug #909 Temporary fix for the styles of the error 500 page (javiereguiluz)

This PR was merged into the master branch.

Discussion
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Temporary fix for the styles of the error 500 page

I know this is not the right fix ... but I can't fix it in any other way.

The error: if you comment the DATABASE_URL config in the .env file, you see a 500 error. In production, that 500 error page sometimes has CSS styles and sometimes hasn't. Example:

* This page shows styles: http://symfony-demo.test/index.php/en/blog/posts/lorem-ipsum-dolor-sit-amet-consectetur-adipiscing-elit
* This page doesn't: http://symfony-demo.test/index.php/en/blog/

This is just a temporary fix because we need the Symfony Demo to work perfectly for some SymfonyCon session.

Commits
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7196406 Temporary fix for the styles of the error 500 page

Author: javiereguiluz

templates/bundles/TwigBundle/Exception/error500.html.twig

@@ -10,6 +10,11 @@
 
 {% extends 'base.html.twig' %}
 
+{% block stylesheets %}
+    {{ parent() }}
+    <link rel="stylesheet" href="/build/css/app.4aa95248.css">
+{% endblock %}
+
 {% block body_id 'error' %}
 
 {% block main %}