ActiveRecord::record_timestamps broken in RC2 (regression from RC1)

Just noticed that ActiveRecord::Base.record_timestamps = false no longer prevents timestamps from being updated. This is a regression in RC2; the issue was not present in RC1.

Demo using an "Article" mode in a rails console session:

>> a=Article.first
  Article Load (0.2ms)  SELECT `articles`.* FROM `articles` LIMIT 1
>> Article.record_timestamps
=> true
>> Article.record_timestamps = false
=> false
>> Article.record_timestamps
=> false
>> a.public = false
=> false
>> a.save
  SQL (0.2ms)  UPDATE `articles` SET `public` = 0, `updated_at` = '2010-08-24 12:25:58' WHERE (`articles`.`id` = 1)

Same bug occurs when setting the record_timestamps value on ActiveRecord::Base itself:

>> ActiveRecord::Base.record_timestamps 
=> true
>> ActiveRecord::Base.record_timestamps = false
=> false
>> a=Article.first
  Article Load (0.2ms)  SELECT `articles`.* FROM `articles` LIMIT 1
>> a.public=true
=> true
>> a.save
  SQL (0.2ms)  UPDATE `articles` SET `public` = 1, `updated_at` = '2010-08-24 12:27:11' WHERE (`articles`.`id` = 1)

Going to use git bisect to see if I can locate the bad commit. There are a couple of candidates I can see in the history that touch code in the record_timestamps path. Will post back once I've found the commit.