Fix data-admin-url model lookup for Django 1.8 ContentType

Django 1.8 ContentType has changed the behaviour of "name" and
in some cases the previous version no longer returns a valid URL.
The correct parameter to use for the Model name is the "model"
parameter of the ContentType object.

django_admin_bootstrapped/widgets.py

@@ -24,7 +24,7 @@ def render_option(self, selected_choices, option_value, option_label):
             extra_attrs = {
                 'data-generic-lookup-enabled': 'yes',
                 'data-admin-url': silent_reverse('admin:{0.app_label}_' \
-                                             '{0.name}_changelist'.format(ct)),
+                                             '{0.model}_changelist'.format(ct)),
             }
 
         if option_value in selected_choices: