This upgrades DOT by reverting the revert.

This reverts commit 4d8b9c36

ARCH-180

Version bump for edx-enterprise. This version contains a fix for enterprise customer admin screen 500 error.

This is to upgrade the ddt package from the old 0.8.0 version to the latest version that supports Python3
(version 1.2.0 as of this commit)

This commit is intended to close INCR-6 issue (see https://openedx.atlassian.net/browse/INCR-6 )

ARCH-223

We added a migration to a ManyToMany key in both directions and that had
to be done with RunSQL which requires sqlparse
https://docs.djangoproject.com/en/1.11/ref/migration-operations/#runsql

ARCH-223

ARCH-220

ARCH-193

18.0 seems to be doing a different thing with REMOTE_ADDR.

Putting this back to the last working version in production.

There is a breaking change in gunicorn 19 which changes
the behavior of the `REMOTE_ADDR` request meta info. It
no longer correctly passes through the value of X-Forwarded-For
if that header is present.

This resulted in making anything that looked at this attribute
think that all requests were coming from 127.0.0.1

This broke the django-ratelimit-backend library which relies on
this feature to determine if a user has had too many login attempts.

Gunicorn Change Log: http://docs.gunicorn.org/en/stable/2015-news.html

There are issues in the newest version that we don't want to pick up yet.

We're quite far behind, let's start by just looking at the treadmill.

PLAT-2254