[Fix] Updated the kapack pinning.

kapack.json

 {
-  "url": "https://github.com/oar-team/kapack.git",
-  "rev": "d173f5042764dfe5755b9d705ba84523d184e31e",
-  "date": "2018-10-25T14:57:27+02:00",
-  "sha256": "1rpnfhwk6jyhampqklcy4n8688aq8yz04k96ifn8n8fml6s5bzkb",
+  "url": "https://github.com/freuk/kapack.git",
+  "rev": "8264261535d26b371de1fb05ed89bee895b2bc6a",
+  "date": "2018-11-05T10:33:52-06:00",
+  "sha256": "16g7p6pq4xs1wsycanmi88290g0p5q18jk6kh6134gchkk9l9cbf",
   "fetchSubmodules": true
 }

pin.nix

 {
   hostPkgs ? import <nixpkgs> {},
-  jsonpath
+  jsonpath,
+  depset ? {}
 }:
   let
     pinnedVersion = hostPkgs.lib.importJSON jsonpath;
     pinnedPkgs = hostPkgs.fetchgit {
       inherit (pinnedVersion) url rev sha256;
     };
-  in import pinnedPkgs {}
+  in import pinnedPkgs depset

pkgs/default.nix

 {
-  hostNixpkgs  ? <nixpkgs>,
-  kapack       ? import ../pin.nix { hostPkgs = import hostNixpkgs {}; jsonpath=../kapack.json; },
-  pkgs         ? import ../pin.nix { hostPkgs = import hostNixpkgs {}; jsonpath =../nixpkgs-18.03.json; },
+  hostPkgs  ? import <nixpkgs> {},
+  kapack       ? import ../pin.nix { inherit hostPkgs; jsonpath=../kapack.json; depset = {inherit hostPkgs;};},
+  pkgs         ? import ../pin.nix { inherit hostPkgs; jsonpath=../nixpkgs-18.03.json; },
 }:
 let
   gitpin = f: pkgs.fetchgit {inherit (pkgs.lib.importJSON f) url sha256 rev fetchSubmodules;};