t4129: fix setfacl-related permissions failure

When running this test in Cygwin, it's necessary to remove the inherited
access control lists from the Git working directory in order for later
permissions tests to work as expected.

As such, fix an error in the test script so that the ACLs are set for
the working directory, not a nonexistent subdirectory.

Signed-off-by: Adam Dinwoodie <adam@dinwoodie.org>
Reviewed-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t4129-apply-samemode.sh

@@ -78,7 +78,7 @@ test_expect_success POSIXPERM 'do not use core.sharedRepository for working tree
 	test_config core.sharedRepository 0666 &&
 	(
 		# Remove a default ACL if possible.
-		(setfacl -k newdir 2>/dev/null || true) &&
+		(setfacl -k . 2>/dev/null || true) &&
 		umask 0077 &&
 
 		# Test both files (f1) and leading dirs (d)