contrib/wix/hg.cmd

index: don't include nullid in boundary check in pure code

Yet another change that should probably have been part of a3dacabd476b
(index: don't allow index[len(index)] to mean nullid, 2018-07-20).

Differential Revision: https://phab.mercurial-scm.org/D4333

@echo off
rem launch hg.exe from parent folder
"%~dp0\..\hg.exe" %*