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.
{
    std::vector<std::string> result;
    for (const util::SettingsValue& value : GetSettingsList(strArg)) {
        result.push_back(value.isFalse() ? "0" : value.isTrue() ? "1" : value.get_str());
    }
    return result;
}
bool ArgsManager::IsArgSet(const std::string& strArg) const
{
    return !GetSetting(strArg).isNull();
}
bool ArgsManager::InitSettings(std::string& error)
{
    if (!GetSettingsPath()) {
        return true; 
    }
    std::vector<std::string> errors;
    if (!ReadSettingsFile(&errors)) {
        error = strprintf("Failed loading settings file:\n%s\n", MakeUnorderedList(errors));
        return false;
    }
    if (!WriteSettingsFile(&errors)) {
        error = strprintf("Failed saving settings file:\n%s\n", MakeUnorderedList(errors));
        return false;
    }
    return true;
}
bool ArgsManager::GetSettingsPath(fs::path* filepath, bool temp, bool backup) const