Merge pull request ipfs/go-ipns#17 from ipfs/fix/extract-public-key

use new ExtractPublicKey signature

This commit was moved from ipfs/go-ipns@d73bc7a

ipns/ipns.go

@@ -73,13 +73,10 @@ func EmbedPublicKey(pk ic.PubKey, entry *pb.IpnsEntry) error {
 	if err != nil {
 		return err
 	}
-	extracted, err := id.ExtractPublicKey()
-	if err != nil {
+	if _, err := id.ExtractPublicKey(); err != peer.ErrNoPublicKey {
+		// Either a *real* error or nil.
 		return err
 	}
-	if extracted != nil {
-		return nil
-	}
 
 	// We failed to extract the public key from the peer ID, embed it in the
 	// record.

ipns/record.go

@@ -61,12 +61,12 @@ func (v Validator) Validate(key string, value []byte) error {
 }
 
 func (v Validator) getPublicKey(pid peer.ID, entry *pb.IpnsEntry) (ic.PubKey, error) {
-	pk, err := ExtractPublicKey(pid, entry)
-	if err != nil {
-		return nil, err
-	}
-	if pk != nil {
+	switch pk, err := ExtractPublicKey(pid, entry); err {
+	case peer.ErrNoPublicKey:
+	case nil:
 		return pk, nil
+	default:
+		return nil, err
 	}
 
 	if v.KeyBook == nil {