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.
{
    {
        LOCK(cs_args);
        m_settings.ro_config.clear();
        m_config_sections.clear();
    }
    const fs::path conf_path = GetPathArg("-conf", BITCOIN_CONF_FILENAME);
    std::ifstream stream{GetConfigFile(conf_path)};
    
    if (IsArgSet("-conf") && !stream.good()) {
        error = strprintf("specified config file \"%s\" could not be opened.", fs::PathToString(conf_path));
        return false;
    }
    
    if (stream.good()) {
        if (!ReadConfigStream(stream, fs::PathToString(conf_path), error, ignore_invalid_keys)) {
            return false;
        }
        
        
        bool use_conf_file{true};
        {
            LOCK(cs_args);
            if (auto* includes = util::FindKey(m_settings.command_line_options, "includeconf")) {