Enable disposable preload service via preset

Fixes: QubesOS/qubes-issues#10146
For: QubesOS/qubes-issues#1512

Author: ben-grande

rpm_spec/core-dom0.spec.in

@@ -155,6 +155,7 @@ mkdir -p $RPM_BUILD_ROOT/etc/qubes/backup
 %systemd_post qubes-core.service
 %systemd_post qubes-qmemman.service
 %systemd_post qubesd.service
+%systemd_post qubes-preload-dispvm.service
 
 sed '/^autoballoon=/d;/^lockfile=/d' -i /etc/xen/xl.conf
 echo 'autoballoon=0' >> /etc/xen/xl.conf
@@ -190,6 +191,7 @@ fi
 %systemd_preun qubes-core.service
 %systemd_preun qubes-qmemman.service
 %systemd_preun qubesd.service
+%systemd_preun qubes-preload-dispvm.service
 
 if [ "$1" = 0 ] ; then
 	# no more packages left
@@ -201,6 +203,7 @@ fi
 %systemd_postun qubes-core.service
 %systemd_postun_with_restart qubes-qmemman.service
 %systemd_postun_with_restart qubesd.service
+%systemd_postun qubes-preload-dispvm.service
 
 if [ "$1" = 0 ] ; then
 	# no more packages left