spark-wallet/generate: remove supplement.json

This file is empty and has no effect.

pkgs/spark-wallet/composition.nix

@@ -5,10 +5,6 @@
   }, system ? builtins.currentSystem, nodejs ? pkgs."nodejs-10_x"}:
 
 let
-  globalBuildInputs = pkgs.lib.attrValues (import ./supplement.nix {
-    inherit nodeEnv;
-    inherit (pkgs) fetchurl fetchgit;
-  });
   nodeEnv = import ./node-env.nix {
     inherit (pkgs) stdenv python2 utillinux runCommand writeTextFile;
     inherit nodejs;
@@ -17,5 +13,5 @@ let
 in
 import ./node-packages.nix {
   inherit (pkgs) fetchurl fetchgit;
-  inherit nodeEnv globalBuildInputs;
+  inherit nodeEnv;
 }