util: copyfile: remove dest before copying
This prevents spurious problems writing to locked files on Windows.
@echo off
rem Windows Driver script for Mercurial
setlocal
set HG=%~f0
rem Use a full path to Python (relative to this script) as the standard Python
rem install does not put python.exe on the PATH...
rem %~dp0 is the directory of this script
"%~dp0..\python" "%~dp0hg" %*
endlocal