Start start-cluster-installation when enabling it

Enabling a systemd service required by a target that is already in
progress doesn't actually result in it starting, because systemd does
not rebuild its run queue from the existing transaction. To get around
this, explicitly start the start-cluster-installation service when we
enable it in the appliance.

Author: zaneb

data/data/agent/files/usr/local/bin/load-config-iso.sh

@@ -82,7 +82,7 @@ copy_archive_contents() {
        is_enabled=$(systemctl is-enabled "$service")
        if [[ "${is_enabled}" == "disabled" ]]; then
           echo "Service ${service} is disabled, enabling it"
-          systemctl enable "${service}"
+          systemctl --no-block --now enable "${service}"
        fi
     done