fixed typo

src/Symfony/Bundle/WebProfilerBundle/Resources/views/Collector/request.html.twig

@@ -78,7 +78,7 @@
     <h2>Request Content</h2>
 
     <p>
-        {% if collector.content is false %}
+        {% if collector.content == false %}
             <em>Request content not available (it was retrieved as a resource).</em>
         {% elseif collector.content %}
             <pre>{{ collector.content }}</pre>