always return info on exact matches in find peer

This way, users who are actually trying to find a peer (not just nodes near a
key in the DHT) can find that peer, even if they aren't a DHT server and/or
aren't in anyone's routing table.

fixes #161

handlers.go

@@ -270,6 +270,11 @@ func (dht *IpfsDHT) handleFindPeer(ctx context.Context, p peer.ID, pmes *pb.Mess
 		closest = []peer.ID{dht.self}
 	} else {
 		closest = dht.betterPeersToQuery(pmes, p, CloserPeerCount)
+		// If we have information on the requested peer, add that even
+		// if they're not in our routing table.
+		if len(dht.peerstore.Addrs(p)) > 0 {
+			closest = append(closest, p)
+		}
 	}
 
 	if closest == nil {