evolve: be more complete about copying extra from old revisions For 'hg evolve' we want to copy all extra-level metadata except for branch. This keeps the experimental topics extension from getting obliterated by evolve runs. Many hashes in tests changed due to some extra data coming along for the ride in various places, but no functionality that was tested. It's plausible that this copies too much metadata - maybe we should be dropping rebase_src or convert_revision as well. Right now no tools do that, so I'm biasing towards preserving everything except branch when copying metadata for now.