hackage-packages.nix: update Haskell package set

This update was generated by hackage2nix v20151217 using the following inputs:

  - Nixpkgs: https://github.com/NixOS/nixpkgs/commit/1e4c0752db037bd56ee5731098a5fb3fe12da18c
  - Hackage: https://github.com/commercialhaskell/all-cabal-hashes/commit/42db5021ee1a4b501ec28e7d32a17b76a6b49e74
  - LTS Haskell: https://github.com/fpco/lts-haskell/commit/253d4da34232ee2e34c825f5937f836f3374abd1
  - Stackage Nightly: https://github.com/fpco/stackage-nightly/commit/57c8505aea9ea07de3bc4e319a583befbb124ea4