fetchurl: Remove some compatibility hacks
fetchurl: Don't wait too long for the hashed mirrors

If the hashed mirror (nixos.org/tarballs) doesn't respond in 15
seconds, give up and try the original URL.
sysbench: Fix URL
warsow: Update to 1.03.
Add Haskell package stm-conduit

This adds the dependency stm-chans as well.
Add Haskell package `cereal-conduit'
Merge remote-tracking branch 'upstream/master'