[#50] ir: Fix config property name for prometheus

Signed-off-by: Anton Nikiforov <an.nikiforov@yadro.com>

pkg/innerring/innerring.go

@@ -925,7 +925,7 @@ func New(ctx context.Context, log *logger.Logger, cfg *viper.Viper, errChan chan
 		queueSize: cfg.GetUint32("workers.subnet"),
 	})
 
-	if cfg.GetString("metrics.address") != "" {
+	if cfg.GetString("prometheus.address") != "" {
 		m := metrics.NewInnerRingMetrics()
 		server.metrics = &m
 	}