Do not ignore updated services when cleaning up removed ones

When cleaning up removed services, the assumption was made that if a
service was not 'removed', it was 'clean'. In reality, it could also
be 'updated', which was then overwritten, causing services not being
restarted. Don't do that.

As a future precaution, make the dirty field const, only allowing
updates from accessor methods.

service.c

@@ -844,7 +844,7 @@ restart:
 				break;
 			}
 
-			svc->dirty = 0;
+			svc_mark_clean(svc);
 
 			switch (svc->type) {
 			case SVC_TYPE_SERVICE:
@@ -898,7 +898,7 @@ restart:
 				service_stop(svc);
 				*state = SVC_STOPPING_STATE;
 			}
-			svc->dirty = 0;
+			svc_mark_clean(svc);
 		}
 
 		break;