Remove unnecessary variables from base.html (#454)

bakerydemo/templates/base.html

@@ -32,7 +32,7 @@
         {% wagtailuserbar %}
 
         {% block header %}
-            {% include "includes/header.html" with parent=site_root calling_page=self %}
+            {% include "includes/header.html" %}
         {% endblock header %}
 
         {% block breadcrumbs %}