Remove warning, remove not used variable, and make methods private

Warning: "shadowing outer local variable - routes".

actionpack/lib/action_dispatch/routing/inspector.rb

@@ -75,13 +75,15 @@ def format(formatter, filter = nil)
         routes = collect_routes(routes_to_display)
         formatter.section :application, 'Application routes', routes
 
-        @engines.each do |name, routes|
-          formatter.section :engine, "Routes for #{name}", routes
+        @engines.each do |name, engine_routes|
+          formatter.section :engine, "Routes for #{name}", engine_routes
         end
 
         formatter.result
       end
 
+      private
+
       def filter_routes(filter)
         if filter
           @routes.select { |route| route.defaults[:controller] == filter }
@@ -91,7 +93,7 @@ def filter_routes(filter)
       end
 
       def collect_routes(routes)
-        routes = routes.collect do |route|
+        routes.collect do |route|
           RouteWrapper.new(route)
         end.reject do |route|
           route.internal?