Fixed #7198 -- Improved error message when missing models.py. Thanks Silver_Ghost and for the patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16876 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/loading.py

@@ -146,6 +146,7 @@ class AppCache(object):
                     if mod is None:
                         if emptyOK:
                             return None
+                        raise ImproperlyConfigured("App with label %s is missing a models.py module.")
                     else:
                         return mod
             raise ImproperlyConfigured("App with label %s could not be found" % app_label)