[WebProfilerBundle] Fixed template to work with the new behavior of {% set %}

src/Symfony/Bundle/WebProfilerBundle/Resources/views/Profiler/layout.html.twig

@@ -19,7 +19,7 @@
                 <ul>
                     {% for name, template in templates %}
                         {% set menu %}{{ template.renderBlock('menu', { 'collector': profiler.get(name)}) }}{% endset %}
-                        {% if menu %}
+                        {% if menu != '' %}
                             <li
                                 {% if name == panel %}class="selected"{% endif %}
                             >