unpack-trees: avoid nuking untracked dir in way of locally deleted file

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/t/t2500-untracked-overwriting.sh b/t/t2500-untracked-overwriting.sh
index 5ec6605..5c0bf4d 100755
--- a/t/t2500-untracked-overwriting.sh
+++ b/t/t2500-untracked-overwriting.sh
@@ -218,7 +218,7 @@
 	)
 '
 
-test_expect_failure 'git am --skip and untracked dir vs deleted file' '
+test_expect_success 'git am --skip and untracked dir vs deleted file' '
 	test_setup_sequencing am_skip_and_untracked &&
 	(
 		cd sequencing_am_skip_and_untracked &&