Using Bitcoin Core v0.15.1

I have just set `onlynet=onion` in my `bitcoin.conf` file and have the following in my logs after node restart:

    2018-02-03 12:40:52 receive version message: /Satoshi:0.15.1/: version 70015, blocks=507429, us={IPv4}:{port), peer=0
    2018-02-03 12:41:15 receive version message: /Satoshi:0.14.2/: version 70015, blocks=507429, us={IPv4}:{port), peer=2
    2018-02-03 12:41:22 receive version message: /Satoshi:0.14.2/: version 70015, blocks=507429, us={IPv4}:{port), peer=3
    2018-02-03 12:41:28 receive version message: /Satoshi:0.15.0/: version 70015, blocks=507429, us={IPv4}:{port), peer=4
    2018-02-03 12:41:57 receive version message: /Satoshi:0.15.99/: version 70015, blocks=526679, us={IPv4}:{port), peer=5
    ...
    2018-02-03 12:44:11 receive version message: /Satoshi:0.15.1/: version 70015, blocks=507429, us=[::]:0, peer=6

The peer 6 was an onion.

My `bitcoin.conf` file is as follows:

    uacomment={redacted}
    prune=10239
    banscore=10
    bantime=31536000
    maxmempool=900
    mempoolexpiry=2160
    proxy=127.0.0.1:9050
    listen=1
    bind=127.0.0.1
    onlynet=onion

All the `Used for reaching peers via` tick boxes are still ticked but disabled when I look in Options>Newtork.

Bitcoin Core should not initiate IPv4 (or IPv6) connections when `onlynet=onion`.  These connections should not be seed nodes due to low addresses:

    2018-02-03 12:40:30 Loaded 66198 addresses from peers.dat  254ms

I get some IPv4 version messages each time I restart the node.

Note: added both `dns=0` and `dnsseed=0` at the same time and this *seems* to resolve the issue with limited testing. These entries should not be necessary to limit IPv4 outgoing connect.

If people need to setup Tor for testing, the setup I have used is here on [Bitcoin.SE](https://bitcoin.stackexchange.com/a/70070/75001)
}
    }
     ********************************************************* Step 9: load wallet
    for (const auto& client : node.chain_clients) {
        if (!client->load()) {
            return false;
        }
    }
     ***
     if pruning, perform the initial blockstore prune
     after any wallet rescanning has taken place.
    if (fPruneMode) {
        if (!fReindex) {
            LOCK(cs_main);
            for (CChainState* chainstate : chainman.GetAll()) {
                uiInterface.InitMessage(_("Pruning blockstore…").translated);
                chainstate->PruneAndFlush();
            }
        }
    } else {
        LogPrintf("Setting NODE_NETWORK on non-prune mode\n");
        nLocalServices = ServiceFlags(nLocalServices | NODE_NETWORK);
    }
     ********************************************************* Step 11: import blocks
    if (!CheckDiskSpace(gArgs.GetDataDirNet())) {
        InitError(strprintf(_("Error: Disk space is low for %s"), fs::quoted(fs::PathToString(gArgs.GetDataDirNet()))));
        return false;
    }
    if (!CheckDiskSpace(gArgs.GetBlocksDirPath())) {
        InitError(strprintf(_("Error: Disk space is low for %s"), fs::quoted(fs::PathToString(gArgs.GetBlocksDirPath()))));