title: Django admin different inlines for change and add view
body: <p>I need separate views for add and change page. In add page I'd like to exclude some fields from inline formset. I've prepared two TabularInline classes, one of them contains property 'exclude'. I tried to use them as follows:</p>
  
  <pre><code>class BoxAdmin(admin.ModelAdmin):
      def change_view(self, request, obj_id):
          self.inlines=[ItemChangeInline,]
          return super(BoxAdmin, self).change_view(self.request, obj_id)
      def add_view(self, request):
          self.inlines=[ItemAddInline,]
          return super(BoxAdmin, self).add_view(self, request)
  </code></pre>
  
  <p>with no effect (no inline is shown at all).</p>