hackage-packages.nix: update Haskell package set

This update was generated by hackage2nix v20150922-36-ge0ee7ef using the following inputs:

  - Nixpkgs: https://github.com/NixOS/nixpkgs/commit/7c001f31b0626f380947c484a308567a2d4397d4
  - Hackage: https://github.com/commercialhaskell/all-cabal-hashes/commit/46f2de463b1405cc9a58aba91ee215bd32894e33
  - LTS Haskell: https://github.com/fpco/lts-haskell/commit/1ae555e197af31e8d2cd56ac766ee2f085fcc6ee
  - Stackage Nightly: https://github.com/fpco/stackage-nightly/commit/4113b2e369fb5bff8cee9d5c02a9788d5569abed