hackage-packages.nix: update Haskell package set

This update was generated by hackage2nix v20150922-47-ga631ea6 using the following inputs:

  - Nixpkgs: https://github.com/NixOS/nixpkgs/commit/e64881f25c2b1850f3198b5df804bd3dfbda0359
  - Hackage: https://github.com/commercialhaskell/all-cabal-hashes/commit/bc415aa435c9ededeccf7bfff34ea846cc2182c5
  - LTS Haskell: https://github.com/fpco/lts-haskell/commit/80256aab763992ee8f057cf8ea250e2077de8f1e
  - Stackage Nightly: https://github.com/fpco/stackage-nightly/commit/fd1a4b498e315172edbff27ec7c984f9f37bb90c