platformio-fhs: minor changes

pkgs/development/arduino/platformio/chrootenv.nix

@@ -1,18 +1,7 @@
-{ lib, buildFHSUserEnv, platformio, stdenv }:
-
-buildFHSUserEnv {
-  name = "platformio";
-
-  targetPkgs = pkgs: (with pkgs;
-    [
-      python27Packages.python
-      python27Packages.setuptools
-      python27Packages.pip
-      python27Packages.bottle
-      python27Packages.platformio
-      zlib
-    ]);
-  multiPkgs = pkgs: (with pkgs;
+{ stdenv, lib, buildFHSUserEnv
+}:
+let
+  pio-pkgs = pkgs: (with pkgs;
     [
       python27Packages.python
       python27Packages.setuptools
@@ -21,6 +10,12 @@ buildFHSUserEnv {
       python27Packages.platformio
       zlib
     ]);
+in
+buildFHSUserEnv {
+  name = "platformio";
+
+  targetPkgs = pio-pkgs;
+  multiPkgs = pio-pkgs;
 
   meta = with stdenv.lib; {
     description = "An open source ecosystem for IoT development";