[bundler/bundler] Remove Bundler.rubygems.config_map because it was deprecated.

https://github.com/bundler/bundler/commit/5215ae7fa3

lib/bundler.rb

@@ -150,7 +150,7 @@ module Bundler
     end
 
     def ruby_scope
-      "#{Bundler.rubygems.ruby_engine}/#{Bundler.rubygems.config_map[:ruby_version]}"
+      "#{Bundler.rubygems.ruby_engine}/#{RbConfig::CONFIG["ruby_version"]}"
     end
 
     def user_home

lib/bundler/rubygems_integration.rb

@@ -213,10 +213,6 @@ module Bundler
       Gem::MARSHAL_SPEC_DIR
     end
 
-    def config_map
-      Gem::ConfigMap
-    end
-
     def clear_paths
       Gem.clear_paths
     end