message: Added missing exception.
diff: @@ -42,6 +42,8 @@ namespace Hyperledger.Indy
  return new InvalidParameterException(errorCode);
  case ErrorCode.CommonInvalidState:
  return new InvalidStateException(errorCode);
  + case ErrorCode.CommonInvalidStructure:
  + return new InvalidStructureException(errorCode);
  case ErrorCode.CommonIOError:
  return new IOException(errorCode);
  case ErrorCode.WalletInvalidHandle:
  