After project upgrade from older Django versions and south still left in environment there are errors on Django 1.9+

[Venelin Stoykov]

After project upgrade and if South is not uninstalled from the environment there can be a strange error. There is no need to try to import South if it is not needed.

The obvious workaround/fix is just to remove South from environment, but if user/developer forgets it will see an Error and may not be obvious from the first time what need to do.

[Venelin Stoykov]

Here is the PR https://github.com/neithere/django-autoslug/pull/23 Coveralls is saying that coverege is reduced and this is because of the AutoSlugField.south_field_triple method to which I move the import of modelinspector.