post-form.html: update to follow master template

theme-authentic2/templates/saml/post_form.html

@@ -2,7 +2,6 @@
 {% load i18n %}
 
 {% block title %} {{ title }} {% endblock %}
-{% block bodyargs %}onload="document.forms['saml'].submit()"{% endblock %}
 
 {% block content %}
 <div class="post-redirect">
@@ -33,4 +32,7 @@
         </div>
     </form>
 </div>
+<script>
+  document.forms['saml'].submit()
+</script>
 {% endblock %}