localrepo: add setparents() to adjust dirstate copies (issue3407) The fix introduced in eab9119c5dee was only partially successful. It is correct to turn dirstate 'm' merge records into normal/dirty ones but copy records are lost in the process. To adjust them as well, we need to look in the first parent manifest to know which files were added and preserve only related records. But the dirstate does not have access to changesets, the logic has to moved at another level, in localrepo.