use get_display_label() as id for new choices in BaseQuerySetView.post()

[dparter]

trafficstars

When a user adds a new value to choices as described at "Creation of new choices in the autocomplete form" the returned "id" is always result.pk

BaseQuerySetView.post() should set the id to self.get_result_value(result) for the case where the view is returning a different id.

[jpic]

Agreed, do you want to make a pull request?