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.
return f();
            } catch (const std::exception& e) {
                LogPrintf("%s\n", e.what());
                return std::make_tuple(node::ChainstateLoadStatus::FAILURE, _("Error opening block database"));
            }
        };
        auto [status, error] = catch_exceptions([&]{ return LoadChainstate(chainman, cache_sizes, options); });
        if (status == node::ChainstateLoadStatus::SUCCESS) {
            uiInterface.InitMessage(_("Verifying blocks…").translated);
            if (chainman.m_blockman.m_have_pruned && options.check_blocks > MIN_BLOCKS_TO_KEEP) {
                LogPrintfCategory(BCLog::PRUNE, "pruned datadir may not have more than %d blocks; only checking available blocks\n",
                                  MIN_BLOCKS_TO_KEEP);
            }
            std::tie(status, error) = catch_exceptions([&]{ return VerifyLoadedChainstate(chainman, options);});
            if (status == node::ChainstateLoadStatus::SUCCESS) {
                fLoaded = true;
                LogPrintf(" block index %15dms\n", Ticks<std::chrono::milliseconds>(SteadyClock::now() - load_block_index_start_time));
            }
        }
        if (status == node::ChainstateLoadStatus::FAILURE_INCOMPATIBLE_DB) {
            return InitError(error);
        }
        if (!fLoaded && !ShutdownRequested()) {
             fir
            if (!options.reindex) {
                bool fRet = uiInterface.ThreadSafeQuestion(
                    error + Untranslated(".\n\n") + _("Do you want to rebuild the block database now?"),
                    error.original + ".\nPlease restart with -reindex or -reindex-chainstate to recover.",
                    "", CClientUIInterface::MSG_ERROR | CClientUIInterface::BTN_ABORT);
                if (fRet) {