Try extracting public key from peer identity

See https://github.com/ipfs/go-ipfs/issues/3896. Depends on https://github.com/libp2p/go-libp2p-peer/pull/13.

records.go

@@ -24,8 +24,14 @@ const MaxRecordAge = time.Hour * 36
 func (dht *IpfsDHT) GetPublicKey(ctx context.Context, p peer.ID) (ci.PubKey, error) {
 	log.Debugf("getPublicKey for: %s", p)
 
+	// try extracting from identity.
+	pk := p.ExtractPublicKey()
+	if pk != nil {
+		return pk, nil
+	}
+
 	// check locally.
-	pk := dht.peerstore.PubKey(p)
+	pk = dht.peerstore.PubKey(p)
 	if pk != nil {
 		return pk, nil
 	}