Remove support for bootstrapping non-toolchains and systems

This isn't used if there are no host tools.

Author: fhunleth

lib/nerves/env.ex

@@ -362,20 +362,6 @@ defmodule Nerves.Env do
     # Export nerves package env variables
     Enum.each(packages, &export_package_env/1)
 
-    # Bootstrap all other packages who define a platform
-    toolchain_package = Nerves.Env.toolchain()
-    system_package = Nerves.Env.system()
-
-    packages
-    |> Enum.reject(&(&1 == toolchain_package or &1 == system_package or &1.platform == nil))
-    |> Enum.each(fn
-      %{platform: platform} = pkg ->
-        platform.bootstrap(pkg)
-
-      _ ->
-        :noop
-    end)
-
     System.put_env("NERVES_ENV_BOOTSTRAP", "1")
   end