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This upgrades Django from 1.4.8 to 1.4.9, which takes us from insecure to merely outdated on requires.io

Changes mostly revolve around resolving some password length restriction issues that don't concern us anyway:

https://github.com/django/django/compare/6903d1690a92aa040adfb0c8eb37cf62e4206714...8f36d1fd952f5bc2066a8d33721025351bf2b4ce