convert: make filemap renames consistently override revision renames When the source repository had a revision renaming "$new -> $old", but the filemap a "$old -> $new" rename, the converted revision could use either $new (deleting the file) or $old (keeping the file) when getting the file data, depending on the lexicographical order of those names. So the resulting revision would leave some files untouched (as expected), but delete others arbitrarely.