Remove unused use_sprockets config

actionpack/lib/abstract_controller/asset_paths.rb

@@ -3,7 +3,7 @@ module AssetPaths
     extend ActiveSupport::Concern
 
     included do
-      config_accessor :asset_host, :asset_path, :assets_dir, :javascripts_dir, :stylesheets_dir, :use_sprockets
+      config_accessor :asset_host, :asset_path, :assets_dir, :javascripts_dir, :stylesheets_dir
     end
   end
 end

actionpack/lib/sprockets/railtie.rb

@@ -11,13 +11,6 @@ class Railtie < ::Rails::Railtie
       load "sprockets/assets.rake"
     end
 
-    # Configure ActionController to use sprockets.
-    initializer "sprockets.set_configs", :after => "action_controller.set_configs" do |app|
-      ActiveSupport.on_load(:action_controller) do
-        self.use_sprockets = app.config.assets.enabled
-      end
-    end
-
     # We need to configure this after initialization to ensure we collect
     # paths from all engines. This hook is invoked exactly before routes
     # are compiled, and so that other Railties have an opportunity to