Set proper filename for extlinux.conf

vm.sh

@@ -87,7 +87,8 @@ chroot /mnt setup-timezone -z Europe/Prague
 # Install basic system
 apk --no-cache add apache2-utils gettext
 wget https://repo.spotter.cz/vm.tar.gz -O - | tar xzf - -C /mnt
-envsubst </mnt/boot/extlinux.conf.old >/mnt/boot/extlinux.conf
+envsubst </mnt/boot/extlinux.conf >/mnt/boot/extlinux.conf.new
+mv /mnt/boot/extlinux.conf.new /mnt/boot/extlinux.conf
 chroot /mnt apk --no-cache add bridge ca-certificates curl e2fsprogs-extra gettext iptables kbd-misc logrotate postfix nginx openssh-server openssh-sftp-server util-linux wireguard-virt wireguard-tools-wg spoc@vm vmmgr@vm
 chroot /mnt newaliases
 for SERVICE in cgroups consolefont crond iptables networking nginx ntpd postfix spoc swap urandom vmmgr; do