Revert FIXTURE_MEDIA_REQUIRE_PREFIX

[lieryan]

I feel kinda responsible for this; the FIXTURE_MEDIA_REQUIRE_PREFIX option doesn't actually work. Well, it does what it says, but then when you do ./manage.py loaddata, it will load these file fields with the extra prefixes which obviously doesn't work with the rest of Django. It kinda misses the whole point of the collectmedia and loaddata command.

What will be needed to fix it is a way to extend loaddata command so that it strips the prefix this looks quite difficult cleanly. Either that or wrap loaddata so that it generates temporary fixture files with the media prefix stripped which is then passed to the original loaddata. That also looks quite painful to do.

For now, perhaps the best option is to revert the entire changes and rethink of a different way to denote what is and isn't to be collected by collectmedia.