DEV-1014 bugfix: autodiscover_pre_task broken

tasks/autodiscover_pre_tasks.yml

@@ -148,11 +148,11 @@
           {% if (server.private_net|length) > 0 %}\
             {% for private_net in server.private_net %}\
               {% if private_net.network == stage_private_network_id|int %}\
-                {{ list.append({'service': server.labels.service, 'private_ip': private_net.ip, 'public_ip': server.public_net.ipv4.ip, 'name': server.name, 'id': server.id}) }}\
+                {{ list.append({'service': server.labels.service | default(''), 'private_ip': private_net.ip, 'public_ip': server.public_net.ipv4.ip, 'name': server.name, 'id': server.id}) }}\
               {% endif %}\
             {% endfor %}\
           {% else %}\
-            {{ list.append({'service': server.labels.service, 'private_ip': '-', 'public_ip': server.public_net.ipv4.ip, 'name': server.name, 'id': server.id}) }}\
+            {{ list.append({'service': server.labels.service | default(''), 'private_ip': '-', 'public_ip': server.public_net.ipv4.ip, 'name': server.name, 'id': server.id}) }}\
           {% endif %}\
         {% endif %}\
       {% endfor %}\