Your Blog post just solved a problem that has been plaguing me for more than a year. At first I thought Wordpress didn't update because it required FTP to update, and since my server has no FTP access I assumed I couldn't use the feature.
Today, someone with FTP on their server had the same problem with auto update not working and providing a valid FTP password didn't do anything!
So, 8 hours later, I chown -R apache:apache deactive the auto update plugin, and now update works on all my servers.
Thank you so much for this blog post, Wordpress documentation of their auto update is a miserable failure.