Channel.pm: Actually deliver channel expressions.

So this is the final part which is needed in order to be able to deliver custom channels, everything else is now just polishing.

We do this by simply redirecting to the build product download URL and we use binary_cache_url the same way as in NixChannel.pm.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

Created by  aszlig  on April 26, 2015
JLGDA7AMM6P5J3NAIL4OR4DMG5J7TLCZKPBNOQLNCNKHLLVEX5HQC
In channels
upstream
main
Change contents