UBUNTU: [Packaging] disable hv-kvp-daemon if needed

BugLink: https://bugs.launchpad.net/bugs/2024900

The daemon reads from this vmbus, if it is not present, it will just
exit with an error. Adding this line to the service file will prevent
systemd from trying to start the daemon if the device is not present.

Signed-off-by: Gauthier Jolly <gauthier.jolly@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Andrei Gherzan <andrei.gherzan@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Roxana Nicolescu <roxana.nicolescu@canonical.com>

debian/linux-cloud-tools-common.hv-kvp-daemon.service

@@ -11,6 +11,7 @@ After=sys-devices-virtual-misc-vmbus\x21hv_kvp.device systemd-remount-fs.service
 Before=shutdown.target cloud-init-local.service walinuxagent.service
 Conflicts=shutdown.target
 RequiresMountsFor=/var/lib/hyperv
+ConditionPathExists=/dev/vmbus/hv_kvp
 
 [Service]
 ExecStart=/usr/sbin/hv_kvp_daemon -n