title: Django template keyword `choice_value` in no longer work in 1.11
body: <p>There is a multiple checkbox in template, if value contain in render the choice will checked by default. It works well with 1.10.</p>
  
  <p>form.py:</p>
  
  <pre><code>class NewForm(forms.Form):
      project = forms.ModelMultipleChoiceField(
          widget=forms.CheckboxSelectMultiple, 
          queryset=Project.objects.filter(enable=True)
      )
  </code></pre>
  
  <p>template:</p>
  
  <pre><code>{% for p in form.project %}
  &lt;label for="{{ p.id_for_label }}"&gt;
      &lt;input type="checkbox" name="{{ p.name }}" id="{{ p.id_for_label }}"
          value="{{ p.choice_value }}"
          {% if p.choice_value|add:"0" in form.project.initial %} checked{% endif %}&gt;
      &lt;p&gt;{{ p.choice_label }}&lt;/p&gt;
  &lt;/label&gt;
  {% endfor %}
  </code></pre>
  
  <p>views.py:</p>
  
  <pre><code>def order_start(request, order_id):
      if request.method == 'POST':
          form = NewForm(request.POST)
          if form.is_valid():
              order.end_time = timezone.now()
              order.save()
              order.project = form.cleaned_data['project']
              order.save()
              return HttpResponsec(order.id)
      else:
          form = NewForm(initial={
              'project': [p.pk for p in order.project.all()],
          })
  
      return render(request, 'orders/start.html', {'form': form, 'order': orderc})
  </code></pre>
  
  <p>When I upgrade to Django 1.11, <code>{{ p.name }}</code> and <code>{{ p.choice_value }}</code> return nothing. I know 1.11 has removed <code>choice_value</code>, but how to solve this problem?</p>
  
  <p>1.10 <a href="https://docs.djangoproject.com/en/1.10/_modules/django/forms/widgets/" rel="noreferrer">https://docs.djangoproject.com/en/1.10/_modules/django/forms/widgets/</a><br>
  1.11 <a href="https://docs.djangoproject.com/en/1.11/_modules/django/forms/widgets/" rel="noreferrer">https://docs.djangoproject.com/en/1.11/_modules/django/forms/widgets/</a></p>