[RocksDB] Do not read from disk to update the 'vbstate.highSeqno' in RocksDBKVStore::saveDocs

    // Check and update last seqno

    auto lastSeqno = readHighSeqnoFromDisk(*vbh);

    if (maxDBSeqno != lastSeqno) {

        logger.log(EXTENSION_LOG_WARNING,

                   "RocksDBKVStore::saveDocs: Seqno in db header (%" PRIu64

                   ") is not matched with what was persisted (%" PRIu64

                   ") for vb:%" PRIu16,

                   lastSeqno,

                   maxDBSeqno,

                   vbid);

    }

    vbstate->highSeqno = lastSeqno;