ls-tree: disable negative pathspec because it's not supported

[git] / t / t4135 / add-with quote.diff

diff -pruN a/"postimage".txt b/"postimage".txt
--- a/"postimage".txt   1969-12-31 18:00:00.000000000 -0600
+++ b/"postimage".txt   2010-08-18 20:13:31.756002255 -0500
@@ -0,0 +1 @@
+postimage