Upgrade django from 1.4.8 to 1.4.9

Merge this one first - https://github.com/mozilla/kuma-lib/pull/37

This upgrades Django from 1.4.8 to 1.4.9, which takes us from insecure to [merely outdated on requires.io](https://requires.io/github/lmorchard/kuma/requirements/?branch=upgrade-django-1.4.9)

Changes mostly revolve around resolving some password length restriction issues that don't concern us anyway:

https://github.com/django/django/compare/6903d1690a92aa040adfb0c8eb37cf62e4206714...8f36d1fd952f5bc2066a8d33721025351bf2b4ce