On my Linux Mint 19.1:
```bash
$ umask
0022
```

After the first run of `bitcoin-qt -sysperm=false` the `0700` permissions are expected for both the datadir (`~/.bitcoin`) and the walletdir (`~/.bitcoin/wallets`).

Actually, the directories are created with such access permissions:
```bash
$ stat ~/.bitcoin | grep Uid
Access: (0755/drwxr-xr-x)  Uid: ( 1000/ hebasto)   Gid: ( 1000/ hebasto)
$ stat ~/.bitcoin/wallets | grep Uid
Access: (0755/drwxr-xr-x)  Uid: ( 1000/ hebasto)   Gid: ( 1000/ hebasto)
```

Refs:
- #4286
- #13371
- #13389

NOTE: reading through the initial PR #4286 makes me think it was controversial. Is it a better and simpler way to just get rid of `-sysperm` option? I believe a user who needs this option can easily run `chown` command.
{
    try {
        fs::remove(GetAuthCookieFile());
    } catch (const fs::filesystem_error& e) {
        LogPrintf("%s: Unable to remove random auth cookie file: %s\n", __func__, fsbridge::get_filesystem_error_message(e));
    }
}
std::vector<UniValue> JSONRPCProcessBatchReply(const UniValue& in)
{
    if (!in.isArray()) {
        throw std::runtime_error("Batch must be an array");
    }
    const size_t num {in.size()};
    std::vector<UniValue> batch(num);
    for (const UniValue& rec : in.getValues()) {
        if (!rec.isObject()) {
            throw std::runtime_error("Batch member must be an object");
        }
        size_t id = rec["id"].getInt<int>();
        if (id >= num) {
            throw std::runtime_error("Batch member id is larger than batch size");
        }
        batch[id] = rec;
    }
    return batch;
}
void JSONRPCRequest::parse(const UniValue& valRequest)