title: Django validation error triggered with initial data in modelformset_factory
body: <p>I'm currently running Django 1.4.</p>
  
  <p>When I'm creating a modelformset and provide an initial value to the extra form, Django then runs validation against it and finds that the other required fields are empty and thus throws a validation error.</p>
  
  <p>My code looks something like this:</p>
  
  <pre><code>QueryFormset = modelformset_factory(Query, extra=1, 
      can_delete=True, form=QueryForm
  )
  
  if request.method == "POST":
      qformset = QueryFormset(request.POST)
      if qformset.is_valid():
          qformset.save()
      else:
          # This is where we go when the formset is saved without
          # any values inserted into the extra form
  else:
      qformset = QueryFormset(
          queryset=Query.objects.filter(user=request.user),
          initial=[{'user': request.user}]
      )
  </code></pre>
  
  <p>If I just click save without making any changes to the values of the form (existing forms, or to the extra form) the formset is marked as invalid because the extra form has something in the user field, but is missing the other required fields.</p>
  
  <p>How do I make Django let this pass by? It should throw away the extra form as nothing there has been changed.</p>