16 refactor deprecated functions

Closes https://code.vereign.com/code/data-storage-agent/issues/16

handler/handler.go

@@ -236,9 +236,9 @@ func (s *KeyStorageServerImpl) GetKeyId(ctx context.Context, in *api.GetKeyIdByK
 
 	keyIdResponse := &api.GetKeyIdByKeyResponse{}
 
-	stringMessage, errorsString, err := dataStorageClient.GetString(keyToKeyIdTable, in.PublicKey)
-	if err == nil && errorsString == "" {
-		keyIdResponse.KeyId = stringMessage
+	keyId, errorsString, err := dataStorageClient.GetString(keyToKeyIdTable, in.PublicKey)
+	if err == nil && errorsString == "" && keyId != "" {
+		keyIdResponse.KeyId = keyId
 		return keyIdResponse, nil
 	} else {
 		if err != nil {