relax delta selection filtering in pack-objects

This change provides a 8% saving on the pack size with a 4% CPU time
increase for git-repack -a on the current git archive.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

pack-objects.c

@@ -629,11 +629,10 @@ static int try_delta(struct unpacked *cur, struct unpacked *old, unsigned max_de
 	}
 
 	size = cur_entry->size;
-	if (size < 50)
-		return -1;
 	oldsize = old_entry->size;
 	sizediff = oldsize > size ? oldsize - size : size - oldsize;
-	if (sizediff > size / 8)
+
+	if (size < 50)
 		return -1;
 	if (old_entry->depth >= max_depth)
 		return 0;