Fixed #21489 -- Make formsets directly importable from django.forms.

django/forms/__init__.py

@@ -5,5 +5,6 @@ Django validation and HTML form handling.
 from django.core.exceptions import ValidationError  # NOQA
 from django.forms.fields import *  # NOQA
 from django.forms.forms import *  # NOQA
+from django.forms.formsets import *  # NOQA
 from django.forms.models import *  # NOQA
 from django.forms.widgets import *  # NOQA

django/forms/formsets.py

@@ -13,7 +13,7 @@ from django.utils.six.moves import xrange
 from django.utils.translation import ungettext, ugettext as _
 
 
-__all__ = ('BaseFormSet', 'all_valid')
+__all__ = ('BaseFormSet', 'formset_factory', 'all_valid')
 
 # special field names
 TOTAL_FORM_COUNT = 'TOTAL_FORMS'

django/forms/models.py

@@ -24,7 +24,8 @@ from django.utils.translation import ugettext_lazy as _, ugettext, string_concat
 __all__ = (
     'ModelForm', 'BaseModelForm', 'model_to_dict', 'fields_for_model',
     'save_instance', 'ModelChoiceField', 'ModelMultipleChoiceField',
-    'ALL_FIELDS',
+    'ALL_FIELDS', 'BaseModelFormSet', 'modelformset_factory',
+    'BaseInlineFormSet', 'inlineformset_factory',
 )
 
 ALL_FIELDS = '__all__'