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.
fReindex = true;
                    AbortShutdown();
                } else {
                    LogPrintf("Aborted block database rebuild. Exiting.\n");
                    return false;
                }
            } else {
                return InitError(error);
            }
        }
    }
     As LoadBlockIndex can take several minutes, it's possible the user
     requested to kill the GUI during the last operation. If so, exit.
     As the program has not fully started yet, Shutdown() is possibly overkill.
    if (ShutdownRequested()) {
        LogPrintf("Shutdown requested. Exiting.\n");
        return false;
    }
    ChainstateManager& chainman = *Assert(node.chainman);
    assert(!node.peerman);
    node.peerman = PeerManager::make(*node.connman, *node.addrman, node.banman.get(),
                                     chainman, *node.mempool, ignores_incoming_txs);
    RegisterValidationInterface(node.peerman.get());
     ********************************************************* Step 8: start indexers
    if (args.GetBoolArg("-txindex", DEFAULT_TXINDEX)) {
        if (const auto error{WITH_LOCK(cs_main, return CheckLegacyTxindex(*Assert(chainman.m_blockman.m_block_tree_db)))}) {
            return InitError(*error);
        }
        g_txindex = std::make_unique<TxIndex>(interfaces::MakeChain(node), cache_sizes.tx_index, false, fReindex);
        if (!g_txindex->Start()) {