largefiles: remove confusing handling of .bad return value - it is void

largefiles: fix profile of unused largefilesdirstate._ignore

largefiles: import whole modules instead of importing parts of them Be more friendly to demandimport.

largefiles: update should only create a .orig backup of a largefile once A .orig of a standin after the update do that a .orig of the actual largefile is created. The .orig standin was however never removed again and the largefile .orig was thus overwritten again and again. The fix: remove the standin .orig when it is used.