config: default metric reporting periodicity to 1

src/config.c

@@ -1410,6 +1410,8 @@ static int cntlr_config_get_agent_node(struct controller_config *c,
 
 	if (tb[NODE_RPT_METRIC_PERIODIC])
 		a->report_metric_periodic = atoi(tb[NODE_RPT_METRIC_PERIODIC]->v.string);
+	else
+		a->report_metric_periodic = 1;
 
 	if (tb[NODE_STEER_DISALLOW])
 		a->steer_disallow = atoi(tb[NODE_STEER_DISALLOW]->v.string) == 1 ? true : false;