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.

pull: make discovery phase extensible We apply the same approach as for push and make the discovery extensible. There is only one user in core right now, but we already know we'll need something smarter for obsmarkers. In fact the evolve extension could use this to cleanly extend discovery. The main motivation for this change is consistency between push and pull.

sshpeer: forward stdout of remote "hg init" to appropriate output channel Otherwise, commandserver channel could be corrupted.