hackage-packages.nix: update Haskell package set

This update was generated by hackage2nix v20151217-10-ga610b1b using the following inputs:

  - Nixpkgs: https://github.com/NixOS/nixpkgs/commit/45176e62cac5a125e2766103c6d584ba812da687
  - Hackage: https://github.com/commercialhaskell/all-cabal-hashes/commit/4eb768170375f9a545c38db20ce635b7291ece78
  - LTS Haskell: https://github.com/fpco/lts-haskell/commit/e7c362999942041130d6f66c30289bd6be0430a3
  - Stackage Nightly: https://github.com/fpco/stackage-nightly/commit/a84b3a147a5c0bbaa634f2623ad6e679f33751a1