sorry not able to go to the puddle right now, but change cancel or [lesser option-->] change back-up (two index fingers 'walk' backward) would be my contributions. When you rollback you are reverting to a previous version, cancelling any changes made since that version...
I have been working behind the scenes for a while (along with everything else I do) to translate the menus and messages in Wikipedia into ASL. It has been a long process for many reasons, but one is that I don't really have a whole lot of people to bound off ideas on how to translate some of these things. One example it "rollback". This is a link that allows editors to change an edit back to the previous edit, thereby undoing the current edit. Anyone have any ideas who to translate rollback?