log: follow filenames through renames (issue647) In commands.log a displayer was initialized from cmdutil.show_changeset() with the initial matchfn (which designates the specified files which only is correct in the highest revision in the range). prep() is handed the correct list of files, but displayer.show() didn't use that list but keept using the original matchfn. The matchfn argument to cmdutil.show_changeset() wasn't specified in other places and is only used in .show(), so now we give the matchfn as an optional parameter to .show(). We do however still have to detect --patch and --stat from opts in show_changeset() and let it imply a matchall, but that can now be overruled with the new .show() matchfn parameter.