revert: simplify loop conditional The two breaks can be joined into one. The code gains one level of indent.

revert: explode the action tuple in the for loop noop is about to gain a message.

revert: use actions[...] in all disptable cases 1. Special cases are not special enough 2. There are two cases where nothing is done and a message is displayed. This prepares it.

revset: factorize backup decision The conditional controlling the creation of backup is fairly big. We move config related decisions outside of the loop.