app: use 1 for weight if not specified or wrong

If we have a number of nodes with unspecified weights they'd all be treated
equal which seems to be fair.

app.go

@@ -108,6 +108,9 @@ func newApp(ctx context.Context, opt ...Option) App {
 		if address == "" {
 			break
 		}
+		if weight <= 0 { // unspecified or wrong
+			weight = 1
+		}
 		pb.AddNode(address, weight)
 		a.log.Info("add connection", zap.String("address", address), zap.Float64("weight", weight))
 	}