I think an edit to config.php with that line would have fixed you also. Problem with that method is if they put in a new config.php with the next update then you'd be broken again. If the new php.ini worked in your /includes folder, that is fantastic as that file will not be overwritten in any vb updates and thus keep the "fix" permanently.
Great stuff!
Elmer
The vBulletin software package doesn't actually include a config.php in it for this very reason. They don't want it to overwrite your existing file. The download only contains a config.php.new file which won't overwrite your existing configuration.