Remove Extraneous Check All button from "History" Tab

[Donovan Keith]

Not particularly important, but from a UI standpoint it doesn't make a ton of sense to have an unused column on the History tab. Of course, I'll immediately want it back as soon as it's possible to uninstall using the CV Toolbox.

[Rick Barrett]

Fixed in ca599282.

I'm still leaving the empty column and just removing the header. Pulling the column makes the tree logic messy, and like you said, I'll be adding the checkboxes there soon enough.