message: qt: Revert partially
  The AskPassphraseDialog modal dialog must be synchronous here as
  expected in the WalletModel::requestUnlock() function.
  Fixed an introduced regression.
diff: @@ -291,9 +291,11 @@ void WalletView::unlockWallet()
  {
  // Unlock wallet when requested by wallet model
  if (walletModel->getEncryptionStatus() == WalletModel::Locked) {
  - auto dlg = new AskPassphraseDialog(AskPassphraseDialog::Unlock, this);
  - dlg->setModel(walletModel);
  - GUIUtil::ShowModalDialogAndDeleteOnClose(dlg);
  + AskPassphraseDialog dlg(AskPassphraseDialog::Unlock, this);
  + dlg.setModel(walletModel);
  + // A modal dialog must be synchronous here as expected
  + // in the WalletModel::requestUnlock() function.
  + dlg.exec();
  }
  }
  