gluon-web-model: fix passing additional variables from form template to sections

This is currently unused in our packages.

package/gluon-web-model/files/lib/gluon/web/view/model/form.html

@@ -5,7 +5,7 @@
 	<div class="gluon-form" id="form-<%=id%>">
 		<% if self.title and #self.title > 0 then %><h2 name="content"><%|self.title%></h2><% end %>
 		<% if self.description and #self.description > 0 then %><div class="gluon-form-descr"><%=self.description%></div><% end %>
-		<% self:render_children(renderer) %>
+		<% self:render_children(renderer, scope) %>
 	</div>
 <%- if self.message then %>
 	<div><%|self.message%></div>