nodejs: Drop 4_x packages

nodejs-4_x is scheduled end-of-life on 2018-04-30
It should not go in the 18.03 release

pkgs/development/node-packages/composition-v4.nix

@@ -1,16 +0,0 @@
-# This file has been generated by node2nix 1.5.1. Do not edit!
-
-{pkgs ? import <nixpkgs> {
-    inherit system;
-  }, system ? builtins.currentSystem, nodejs ? pkgs."nodejs-4_x"}:
-
-let
-  nodeEnv = import ./node-env.nix {
-    inherit (pkgs) stdenv python2 utillinux runCommand writeTextFile;
-    inherit nodejs;
-  };
-in
-import ./node-packages-v4.nix {
-  inherit (pkgs) fetchurl fetchgit;
-  inherit nodeEnv;
-}

pkgs/development/node-packages/default-v4.nix

@@ -1,12 +0,0 @@
-{pkgs, system, nodejs, stdenv}:
-
-let
-  nodePackages = import ./composition-v4.nix {
-    inherit pkgs system nodejs;
-  };
-in
-nodePackages // {
-  node-inspector = nodePackages.node-inspector.override (oldAttrs: {
-    buildInputs = oldAttrs.buildInputs ++ [ nodePackages.node-pre-gyp ];
-  });
-}

pkgs/development/node-packages/node-packages-v4.json

@@ -1,9 +0,0 @@
-[
-  "coffee-script"
-, "grunt-cli"
-, "gulp"
-, "node-gyp"
-, "node-inspector"
-, "node-pre-gyp"
-, "npm"
-]