Skip turbolinks for engine test application

When `rails new plugin` is invoked, turbolinks should be skipped in the dummy
test application generated by the plugin generator.

railties/lib/rails/generators/rails/plugin/plugin_generator.rb

@@ -92,6 +92,7 @@ def generate_test_dummy(force = false)
       opts[:api] = options.api?
       opts[:skip_listen] = true
       opts[:skip_git] = true
+      opts[:skip_turbolinks] = true
 
       invoke Rails::Generators::AppGenerator,
         [ File.expand_path(dummy_path, destination_root) ], opts