Rails 5.0 doesn't equip :action_controller_api on_load hook

this reverts 96a8a39 with an improvement

Author: amatsuda

lib/jbuilder/railtie.rb

@@ -16,9 +16,11 @@ module ApiRendering
           end
         end
 
-        ActiveSupport.on_load :action_controller_api do
-          include ActionController::Helpers
-          include ActionController::ImplicitRender
+        ActiveSupport.on_load :action_controller do
+          if name == 'ActionController::API'
+            include ActionController::Helpers
+            include ActionController::ImplicitRender
+          end
         end
       end
     end