Remove code for unsupported versions of Rails from open_id_authentication (#32297).

Patch by Go MAEDA.


git-svn-id: http://svn.redmine.org/redmine/trunk@18788 e93f8b46-1217-0410-a6f0-8f06a7374b81

lib/plugins/open_id_authentication/init.rb

@@ -1,9 +1,5 @@
 # frozen_string_literal: false
 
-if Rails.version < '3'
-  config.gem 'rack-openid', :lib => 'rack/openid', :version => '>=0.2.1'
-end
-
 require 'open_id_authentication'
 
 config.middleware.use OpenIdAuthentication