Fixed #12245 -- Corrected target app handling for auto-generated m2m models when the parent model isn't in the models module (or a subpackage thereof). Thanks to emulbreh for the report and patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@11755 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/fields/related.py

@@ -835,20 +835,13 @@ def create_many_to_many_intermediary_model(field, klass):
         'db_table': field._get_m2m_db_table(klass._meta),
         'managed': managed,
         'auto_created': klass,
+        'app_label': klass._meta.app_label,
         'unique_together': (from_, to)
     })
-    # If the models have been split into subpackages, klass.__module__
-    # will be the subpackge, not the models module for the app. (See #12168)
-    # Compose the actual models module name by stripping the trailing parts
-    # of the namespace until we find .models
-    parts = klass.__module__.split('.')
-    while parts[-1] != 'models':
-        parts.pop()
-    module = '.'.join(parts)
     # Construct and return the new class.
     return type(name, (models.Model,), {
         'Meta': meta,
-        '__module__': module,
+        '__module__': klass.__module__,
         from_: models.ForeignKey(klass, related_name='%s+' % name),
         to: models.ForeignKey(to_model, related_name='%s+' % name)
     })