sch2fig/TODO: diffing deleted files doesn't quite work yet

sch2fig/TODO

@@ -22,3 +22,5 @@
 - move path name guessing into file.c
 - return indication of whether diff found any differences
 - in diff, pass only options understood by cairo_png
+- git_repository_open_ext does not open repo if the path points to a dead file;
+  need to iterate here, too