phases: inform transaction-related hooks that a phase was moved We do not have enough information to provide finer data, but this is still useful information.

test-bundle2: also test the argument of the changegroup hook We also track execution of the changegroup hook. The important information here is to make sure the information that the transaction was processing a bundle2 is passed to hook. This will let most hooks disable themselves while waiting for the hook concluding bundle2 processing (the one we discovered to be not called for pull in the previous changesets).

test-bundle2: test that we got appropriate hook called with appropriate data We can notice that this transaction wide hook is only happening during push and it is missing changegroup-related information. We'll want to fix this but this is not what this patch is about.

pull: use `stepsdone` instead of `todosteps` The push process uses a `stepsdone` attribute instead of a `todosteps` one (with the logic swapped). We unify the two process by picking the `stepsdone` version. I feel like `stepsdone` better fits extensions that would want to extend the push exchange process.