hackage-packages.nix: update Haskell package set

This update was generated by hackage2nix v20151217-13-g1932303 using the following inputs:

  - Nixpkgs: https://github.com/NixOS/nixpkgs/commit/048b08e2df950731939a3d7281d22215569f1b39
  - Hackage: https://github.com/commercialhaskell/all-cabal-hashes/commit/9380d724dd8842b56412be3cf99d2f170f5d5a2c
  - LTS Haskell: https://github.com/fpco/lts-haskell/commit/d2ad5fe9030deeacf1ed9c9de9045c65e597ca76
  - Stackage Nightly: https://github.com/fpco/stackage-nightly/commit/04ed93d83062a82ff9489964485538e6e2b37ac2