Moving the backwards-compatibilizing to Configuration#read_config_files. @mattr-

lib/jekyll.rb

@@ -67,7 +67,6 @@ module Jekyll
     config = Configuration[Configuration::DEFAULTS]
     override = Configuration[override].stringify_keys
     config = config.read_config_files(config.config_files(override))
-    config = config.backwards_compatibilize
 
     # Merge DEFAULTS < _config.yml < override
     config.deep_merge(override).stringify_keys

lib/jekyll/configuration.rb

@@ -128,7 +128,7 @@ module Jekyll
         $stderr.puts "#{err}"
       end
 
-      configuration
+      configuration.backwards_compatibilize
     end
 
     # Public: Ensure the proper options are set in the configuration to allow for