Update django-waffle to use clintonb's fix for django 1.8+

[pomegranited]

Uses @clintonb 's django-waffle==0.21.0 to fix errors when using waffle_switch and waffle_flag management commands.

JIRA tickets: OSPR

Discussions: cf jazzband/django-waffle#244, jsocol/django-waffle@v0.12.0

Partner information: 3rd party hosted

Deployment targets: insights.edx.org, insights.stage.edx.org

Merge deadline: open-releae/ginkgo.rc1, if possible cc @nedbat

Testing instructions:

1. Deploy Insights on an analytics devstack using the current master.
2. Try listing the waffle flags:

   sudo su insights
   ./manage.py waffle_switch --list --settings=analytics_dashboard.settings.production
   

   Note AttributeError: type object 'BaseCommand' has no attribute 'option_list'
3. Checkout the branch from this PR: jill/update-django-waffle
4. Install the pip requirements to upgrade django-waffle:

   make requirements.py
   

5. Re-run the waffle_switch command from step 2, and note success.

Reviewers

• OpenCraft reviewer TBD
• edX reviewers TBD - @edx/analytics CC @thallada

[openedx-webhooks]

Thanks for the pull request, @pomegranited! It looks like you're a member of a company that does contract work for edX. If you're doing this work as part of a paid contract with edX, you should talk to edX about who will review this pull request. If this work is not part of a paid contract with edX, then you should ensure that there is an OSPR issue to track this work in JIRA, so that we don't lose track of your pull request.

Create an OSPR issue for this pull request.

[codecov-io]

Codecov Report

Merging #706 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #706   +/-   ##
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  Coverage   94.85%   94.85%           
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  Files          73       73           
  Lines        5775     5775           
  Branches      490      490           
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  Hits         5478     5478           
  Misses        219      219           
  Partials       78       78

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[openedx-webhooks]

Thanks for the pull request, @pomegranited! I've created OSPR-1826 to keep track of it in JIRA. JIRA is a place for product owners to prioritize feature reviews by the engineering development teams.

Feel free to add as much of the following information to the ticket:

• supporting documentation
• edx-code email threads
• timeline information ("this must be merged by XX date", and why that is)
• partner information ("this is a course on edx.org")
• any other information that can help Product understand the context for the PR

All technical communication about the code itself will still be done via the GitHub pull request interface. As a reminder, our process documentation is here.

If you like, you can add yourself to the AUTHORS file for this repo, though that isn't required. Please see the CONTRIBUTING file for more information.

[clintonb]

Looks good to me, but someone who actually manages/deploys this application should also sign off.

[thallada]

Thanks @pomegranited ! This looks good to me too 👍

[thallada]

I'm going to merge this and then make a PR to cherry-pick this change into the ginkgo release branch.

[pomegranited]

Thank you @thallada and @clintonb !