Fixed #23127: south_migrations note in docs

--------------------

If you already have pre-existing migrations created with

`South 0.x <http://south.aeracode.org>`_, then the upgrade process to use

`South <http://south.aeracode.org>`_, then the upgrade process to use

``django.db.migrations`` is quite simple:

* Ensure all installs are fully up-to-date with their migrations

initial migration, and you'll need to mark them all as applied using::

    python manage.py migrate --fake yourappnamehere

Libraries/Third-party Apps

~~~~~~~~~~~~~~~~~~~~~~~~~~

If you are a library or app maintainer, and wish to support both South migrations

(for Django 1.6 and below) and Django migrations (for 1.7 and above) you should

keep two parallel migration sets in your app, one in each format.

To aid in this, South 1.0 will automatically look for South-format migrations

in a ``south_migrations`` directory first, before looking in ``migrations``,

meaning that users' projects will transparently use the correct set as long

as you put your South migrations in the ``south_migrations`` directory and

your Django migrations in the ``migrations`` directory.

More information is available in the

`South 1.0 release notes <http://south.readthedocs.org/en/latest/releasenotes/1.0.html#library-migration-path>`_.