security_tracker: Set service to RemainAfterExit

This allows zabbix to monitor the active/failed status of the service.
Otherwise systemd will discard it once the executable exits.

Signed-off-by: Florian Pritz <bluewind@xinu.at>

roles/security_tracker/files/security-tracker-update.service

@@ -3,6 +3,7 @@ Description=Security Tracker update service
 
 [Service]
 Type=oneshot
+RemainAfterExit=yes
 User=security
 Group=security
 WorkingDirectory=/srv/http/security-tracker