strip: make repair.strip transactional to avoid repository corruption Uses a transaction instance from the local repository to journal the truncation of revlog files, such that if a strip only partially completes, hg recover will be able to finish the truncate of all the files. The potential unbundling of changes that have been backed up to be restored later will, in case of an error, have to be unbundled manually. The difference is that it will be possible to recover the repository state so the unbundle can actually succeed.