Don't refer to files that doesn't exist anymore

[challet]

Version 4.0.4 deleted these files but they were still refered to in _media function.

Strangely looks like this bug from 2017 : #43

[challet]

That breaks Django ManifestStaticFilesStorage in production. Not only the request going to the static file, but the page refering to it, since it tries to inject an md5 hash from a file that doesn't exist.