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/a28e076b479ce0ef15fa8d2249718b9154f1ff6a
  - Hackage: https://github.com/commercialhaskell/all-cabal-hashes/commit/c63083af590a6a4f6bcce8b20cdb371a0548bbef
  - LTS Haskell: https://github.com/fpco/lts-haskell/commit/cf055c2754aa9858a857c28595024da1fde9eb14
  - Stackage Nightly: https://github.com/fpco/stackage-nightly/commit/8f10b44c120432146160af46c2e0a5456e3b5a10