message: fix conflicting struct name
diff: @@ -234,11 +234,11 @@ public:
  };
  -struct TransactionNotification
  +struct TransactionNotification2
  {
  public:
  - TransactionNotification() {}
  - TransactionNotification(uint256 _hash, ChangeType _status):
  + TransactionNotification2() {}
  + TransactionNotification2(uint256 _hash, ChangeType _status):
  hash(_hash), status(_status) {}
  void invoke(QObject *ttm)
  @@ -255,7 +255,7 @@ private:
  static void NotifyTransactionChanged(MintingTableModel *ttm, CWallet *wallet, const uint256 &hash, ChangeType status)
  {
  - TransactionNotification notification(hash, status);
  + TransactionNotification2 notification(hash, status);
  notification.invoke(ttm);
  }
  