revert: group action into a single dictionary We had 4 different variables to hold the list of the 4 possibles actions. I'm grouping them in a single dictionary for a few reasons. First, it makes it clearer they are all related and meant to be the final actions performed by revert. Second this simplifies the parameter of the _performrevert function. Finally the two elements in each entry (list and message) have a different consumers in different functions, this change will make it easier to split them in a later commit.