Partially revert 4e89d3f778.

* SiteSetting uses DistributedCache which depends on MessageBus.
  Therefore, we need to initialize MessageBus first.

lib/site_setting_extension.rb

@@ -295,11 +295,11 @@ module SiteSettingExtension
     clean_name = name.to_s.sub("?", "").to_sym
 
     define_singleton_method clean_name do
-      if (c = @containers[provider.current_site])
+      if (c = current[name]).nil?
-        c[name]
-      else
         refresh!
         current[name]
+      else
+        c
       end
     end