Fix a longstanding "off by one" revision authorship bug.

* Fixes old revision data on the fly when you open a post for editing.
* Uses post_name of revisions to store a post version number (-v1), so we know what has been fixed.
* Latest version should also have a revision stored, whereas before it did not.

props adamsilverstein, mdawaffe. fixes #16215.

git-svn-id: http://core.svn.wordpress.org/trunk@23823 1a063a9b-81f0-0310-95a4-ce76da25c4cd