Fix constructor ordering

[aschmahmann]

fixes #697

We seem to have a ordering problem where

go-libp2p-kad-dht/dht.go

Lines 212 to 227 in 7db4172

	// register for event bus and network notifications
	sn, err := newSubscriberNotifiee(dht)
	if err != nil {
	return nil, err
	}
	dht.proc.Go(sn.subscribe)
	// handle providers
	dht.proc.AddChild(dht.ProviderManager.Process())
	dht.proc.Go(dht.populatePeers)
	// go-routine to make sure we ALWAYS have RT peer addresses in the peerstore
	// since RT membership is decoupled from connectivity
	go dht.persistRTPeersInPeerStore()
	dht.proc.Go(dht.rtPeerLoop)

subscriberNotifiee is called before rtPeerLoop is started this means that:

go-libp2p-kad-dht/subscriber_notifee.go

Lines 59 to 64 in 7db4172

	// Fill routing table with currently connected peers that are DHT servers
	dht.plk.Lock()
	defer dht.plk.Unlock()
	for _, p := range dht.host.Network().Peers() {
	dht.peerFound(dht.ctx, p, false)
	}

is called which calls:

go-libp2p-kad-dht/dht.go

Lines 682 to 686 in 7db4172

	select {
	case dht.addPeerToRTChan <- addPeerRTReq{p, queryPeer}:
	case <-dht.ctx.Done():
	return
	}

which happens before we've started processing the channel in rtPeerLoop

go-libp2p-kad-dht/dht.go

Line 626 in 7db4172

case addReq := <-dht.addPeerToRTChan:

[petar]

LGTM.