server: Use default logging configuration instead of zap production one

This fixes problem where logs json changes format of timestamp.

pkg/netutil/netutil.go

@@ -190,12 +190,6 @@ func URLStringsEqual(ctx context.Context, lg *zap.Logger, a []string, b []string
 		}
 		urlsB = append(urlsB, *u)
 	}
-	if lg == nil {
-		lg, _ = zap.NewProduction()
-		if lg == nil {
-			lg = zap.NewExample()
-		}
-	}
 	return urlsEqual(ctx, lg, urlsA, urlsB)
 }