Railties' `config` method instatiates a Rails::Railtie::Configuration
object. Rails::Configuration is not used in this file.

The patch does not replace the file being required with the one for
Rails::Railtie::Configuration because that one is autoloaded. See the
spot where this patch changes double quotes with single quotes.

Rails::Railtie::Configuration does depend on Rails::Configuration, and
it requires it accordingly.