scmutil: handle conflicting files and dirs in origbackuppath When ui.origbackuppath is set, .orig files are stored outside of the working copy. However conflicts can occur when files or directories end up having the same name. These conflicts cause Mercurial to abort, even if they've been created as a result of different backups. Make sure we always replace files or directories in the origbackuppath if they conflict with another file or directory. Test Plan: Add new unit test for conflicting paths. Differential Revision: https://phab.mercurial-scm.org/D680