hackage-packages.nix: update Haskell package set

This update was generated by hackage2nix v20150922-46-gf1bbc76 using the following inputs:

  - Nixpkgs: https://github.com/NixOS/nixpkgs/commit/02a00be50f5307163687bac2d357fe4555076aa6
  - Hackage: https://github.com/commercialhaskell/all-cabal-hashes/commit/2c186df615cfe55a07a0bb095c5901e987aa964a
  - LTS Haskell: https://github.com/fpco/lts-haskell/commit/57dab1c9974199e11130c3da70ffa31480a9ca37
  - Stackage Nightly: https://github.com/fpco/stackage-nightly/commit/c3ba1c0c159d1b77cdb8fd3f338f778d90403f4b