launchers/windows10 : nouvelle shebang line

qemu/launchers/windows10

@@ -1,4 +1,4 @@
-#!/bin/sh -x
+#!/usr/bin/env sh
 export QEMUSH_RAM=4G
 export QEMUSH_BASE=virtiofs,kvm
 [ -z "$QEMUSH_NAME" ] && {
@@ -14,3 +14,4 @@ exec spice \
 	-name "$QEMUSH_NAME" \
 	-device intel-hda -device hda-duplex,audiodev=snd0 \
 	"$@"
+set -x