hackage-packages.nix: update Haskell package set

This update was generated by hackage2nix v20151217-9-geddefc2 using the following inputs:

  - Nixpkgs: https://github.com/NixOS/nixpkgs/commit/4f748814968d78483430954df5f1886a4b363f0c
  - Hackage: https://github.com/commercialhaskell/all-cabal-hashes/commit/b70bc194eff3a4562927c5d3991497b6263b486c
  - LTS Haskell: https://github.com/fpco/lts-haskell/commit/cf055c2754aa9858a857c28595024da1fde9eb14
  - Stackage Nightly: https://github.com/fpco/stackage-nightly/commit/3184791ff4ab56cd3b79b8be1d6271c223a51e37