contrib/editmergeps.bat

py3: wrap tempfile.mkstemp() to use bytes path

This patch just flips the default to use a bytes path on Python 3.
ca1cf9b3cce7 is backed out as the bundlepath should be bytes now.

@echo off
powershell -NoProfile -ExecutionPolicy unrestricted -Command "& '%~dp0\editmergeps.ps1' %*"