MediaPlayerPrivateQTKit claims it supports application/x-diskcopy, breaking downloads.
https://bugs.webkit.org/show_bug.cgi?id=108237

Reviewed by Eric Carlson.

Disclaim any non-'video/' or 'audio/' types which QTKit purports to support.

* platform/graphics/mac/MediaPlayerPrivateQTKit.mm:
(WebCore::addFileTypesToCache):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@141281 268f45cc-cd09-0410-ab3c-d52691b4dbfc