[1.8.x] Improved get_media_prefix template tag example.
[1.8.x] Improved get_media_prefix template tag example.

Backport of 9a4a9a8a49ed3e38f3038b8d6fc7c405256271f1 from master

h4r5h1t/django-hauthy,pquentin/django,pquentin/django,h4r5h1t/django-hauthy,h4r5h1t/django-hauthy,pquentin/django,h4r5h1t/django-hauthy