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.
{
    auto sock = CreateSock(m_control_host);
    if (!sock) {
        throw std::runtime_error("Cannot create socket");
    }
    if (!ConnectSocketDirectly(m_control_host, *sock, nConnectTimeout, true)) {
        throw std::runtime_error(strprintf("Cannot connect to %s", m_control_host.ToString()));
    }
    SendRequestAndGetReply(*sock, "HELLO VERSION MIN=3.1 MAX=3.1");
    return sock;
}
void Session::CheckControlSock()