dirstate: update backup functions to take full backup filename Update the dirstate functions so that the caller supplies the full backup filename rather than just a prefix and suffix. The localrepo code was already hard-coding the fact that the backup name must be (exactly prefix + "dirstate" + suffix): it relied on this in _journalfiles() and undofiles(). Making the caller responsible for specifying the full backup name removes the need for the localrepo code to assume that dirstate._filename is always "dirstate". Differential Revision: https://phab.mercurial-scm.org/D68

util: remove unused ctxmanager This was meant as a substitute for Python's "with" with multiple context managers before we moved to Python 2.7. We're now on 2.7, so we should have no reason to keep ctxmanager. "hg grep --all ctxmanager" says that it was never used anyway. Differential Revision: https://phab.mercurial-scm.org/D73