#297: changing security on a post makes it forbidden to all users

[domtheknight]

If a post is made and the security settings are changed, users attemting to access the post instead see a 403: Forbidden error. (Logged out viewers are redirected to the front page to log in.)

This seems to be the case for open to locked, locked to open, private to locked, private to open, and probably other variations as well.

ETA 2/20 - appears this has been fixed, as well as the related tag-doubling.