Don't abort when backup files already exist. Don't allow alternative names. Rationale: - When the user wants to revert, he shouldn't be stopped from doing this just because some old backups will be overwritten. - To not clobber important files by accident, alternative names for backup files were disabled. As the backup target now has a fixed name, the user doesn't have to be informed about the backup copy (unless --verbose)

adding a
adding b
pushing to ../a
abort: could not lock repository ../a: Permission denied