[BUG] Minion locking addon files

[Wobin]

I've noticed that Minion sometimes (but not always) keeps the file handlers active on the last installed addon, which stops it being registered by the game, and so it doesn't show up on reloadui.

Unfortunately, I can't seem to reliably replicate the issue, as Minion manages to clean up quite well on most occasions.

(Using Win8.1)