Excise use of importJSON

Putting information in external JSON files is IMHO not an improvement
over the idiomatic style of Nix expressions. The use of JSON doesn't
add anything over Nix expressions (in fact it removes expressive
power). And scattering package info over lots of little files makes
packages less readable over having the info in one file.

pkgs/applications/virtualization/virtualbox/default.nix

@@ -18,11 +18,14 @@ let
   python = python2;
   buildType = "release";
 
-  inherit (importJSON ./upstream-info.json) version extpackRev extpack main;
+  extpack = "3982657fd4853bcbc79b9162e618545a479b65aca08e9ced43a904aeeba3ffa5";
+  extpackRev = 112026;
+  main = "98073b1b2adee4e6553df73cb5bb6ea8ed7c3a41a475757716fd9400393bea40";
+  version = "5.1.10";
 
   # See https://github.com/NixOS/nixpkgs/issues/672 for details
   extensionPack = requireFile rec {
-    name = "Oracle_VM_VirtualBox_Extension_Pack-${version}-${extpackRev}.vbox-extpack";
+    name = "Oracle_VM_VirtualBox_Extension_Pack-${version}-${toString extpackRev}.vbox-extpack";
     sha256 = extpack;
     message = ''
       In order to use the extension pack, you need to comply with the VirtualBox Personal Use

pkgs/applications/virtualization/virtualbox/guest-additions/default.nix

@@ -12,7 +12,7 @@ stdenv.mkDerivation {
 
   src = fetchurl {
     url = "http://download.virtualbox.org/virtualbox/${version}/VBoxGuestAdditions_${version}.iso";
-    sha256 = (lib.importJSON ../upstream-info.json).guest;
+    sha256 = "29fa0af66a3dd273b0c383c4adee31a52061d52f57d176b67f444698300b8c41";
   };
 
   KERN_DIR = "${kernel.dev}/lib/modules/*/build";

pkgs/applications/virtualization/virtualbox/upstream-info.json

@@ -1,8 +0,0 @@
-{
-  "__NOTE": "Generated using update.py from the same directory.",
-  "extpack": "3982657fd4853bcbc79b9162e618545a479b65aca08e9ced43a904aeeba3ffa5",
-  "extpackRev": "112026",
-  "guest": "29fa0af66a3dd273b0c383c4adee31a52061d52f57d176b67f444698300b8c41",
-  "main": "98073b1b2adee4e6553df73cb5bb6ea8ed7c3a41a475757716fd9400393bea40",
-  "version": "5.1.10"
-}