Handle Zabbix agent and server both being enabled

This gave an error about the zabbix user uid being defined multiple
times.

Changed files
+2 -2
nixos
modules
services
monitoring
+2 -2
nixos/modules/services/monitoring/zabbix-agent.nix
···
config = mkIf cfg.enable {
-
users.extraUsers = singleton
{ name = "zabbix";
uid = config.ids.uids.zabbix;
description = "Zabbix daemon user";
-
};
systemd.services."zabbix-agent" =
{ description = "Zabbix Agent";
···
config = mkIf cfg.enable {
+
users.extraUsers = mkIf (!config.services.zabbixServer.enable) (singleton
{ name = "zabbix";
uid = config.ids.uids.zabbix;
description = "Zabbix daemon user";
+
});
systemd.services."zabbix-agent" =
{ description = "Zabbix Agent";