t/t3000-ls-files-others.sh: use $SHELL_PATH to run git-new-workdir script

Signed-off-by: Brandon Casey <casey@nrlssc.navy.mil>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t3000-ls-files-others.sh

@@ -77,7 +77,7 @@ test_expect_success SYMLINKS 'ls-files --others with symlinked submodule' '
 	) &&
 	(
 		cd super &&
-		"$TEST_DIRECTORY/../contrib/workdir/git-new-workdir" ../sub sub
+		"$SHELL_PATH" "$TEST_DIRECTORY/../contrib/workdir/git-new-workdir" ../sub sub
 		git ls-files --others --exclude-standard >../actual
 	) &&
 	echo sub/ >expect &&