readded missing django.cascade.page_sections_url
<script type="text/javascript">
django.cascade = django.cascade || {};
django.cascade.sharable_fields = {{ sharable_fields|default:"[]" }};
+ django.cascade.page_sections_url = "{% url 'admin:get_page_sections' %}";
django.cascade.ring_plugin_bases = {{% for key, bases in ring_plugin_bases.items %}
{{ key }}: "[{{ bases|join:", " }}]"{% if not forloop.last %},{% endif %}{% endfor %}
};
