private void shutdownOldLogStorage() {
        this.oldLogStorage.shutdown();
        this.isOldStorageExist = false;
        this.thresholdIndex = 0;
        saveStatusCheckpoint();
    }
HybridLogStorage is used to be compatible with new and old logStorage
@author hzh (642256541@qq.com)
jraft-extension/java-log-storage-impl/src/main/java/com/alipay/sofa/jraft/storage/HybridLogStorage.java