Monitoring\Object\Service: don't load host comment

I'd like to reintroduce those columns, showing last object comment
and so one. Those joins are costly, we can fetch host comments way
easier directly from host object once we are here. But I guess we
don't even need it.

modules/monitoring/library/Monitoring/Object/Service.php

@@ -73,7 +73,6 @@ class Service extends AbstractObject
             'host_unhandled_service_count',
             'host_action_url',
             'host_notes_url',
-            'host_last_comment',
             'host_display_name',
             'host_alias',
             'host_ipv4',