setup_revisions: remember whether a ref was positive or not

This will be required by fast-export, when no commits were
exported, but the refs should be set, of course.

Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Sverre Rabbelier <srabbelier@gmail.com>

object.h

@@ -12,7 +12,7 @@ struct object_array {
 	struct object_array_entry {
 		struct object *item;
 		const char *name;
-		unsigned mode;
+		unsigned mode, flags;
 	} *objects;
 };