cerbero: Remove recursive download support
cerbero: Remove recursive download support

Nothing uses it, and we're moving towards using only urllib2 for
downloads, which doesn't support recursive downloads.

atsushieno/cerbero,fluendo/cerbero,fluendo/cerbero,nirbheek/cerbero,GStreamer/cerbero,nirbheek/cerbero,fluendo/cerbero,GStreamer/cerbero,nirbheek/cerbero,atsushieno/cerbero,atsushieno/cerbero,atsushieno/cerbero,atsushieno/cerbero,GStreamer/cerbero,fluendo/cerbero,fluendo/cerbero,GStreamer/cerbero,GStreamer/cerbero,nirbheek/cerbero