Compile master, and run with `src/qt/bitcoin-qt -regtest -nowallet`. As expected, no icon is displayed. Load and unload a wallet. The `HD` icon remains.

On startup:
![on_startup](https://user-images.githubusercontent.com/863730/72410834-711b4c00-37a4-11ea-9a10-bfcf3db7ce68.png)

After a wallet load and unload:
![after_load_unload](https://user-images.githubusercontent.com/863730/72410838-737da600-37a4-11ea-8854-dd13301c0135.png)

connect(receiveCoinsMenuAction, &QAction::triggered, [this]{ showNormalIfMinimized(); });
    connect(receiveCoinsMenuAction, &QAction::triggered, this, &BitcoinGUI::gotoReceiveCoinsPage);
    connect(historyAction, &QAction::triggered, [this]{ showNormalIfMinimized(); });
    connect(historyAction, &QAction::triggered, this, &BitcoinGUI::gotoHistoryPage);
#endif 
    quitAction = new QAction(tr("E&xit"), this);
    quitAction->setStatusTip(tr("Quit application"));
    quitAction->setShortcut(QKeySequence(Qt::CTRL + Qt::Key_Q));
    quitAction->setMenuRole(QAction::QuitRole);
    aboutAction = new QAction(tr("&About %1").arg(PACKAGE_NAME), this);
    aboutAction->setStatusTip(tr("Show information about %1").arg(PACKAGE_NAME));
    aboutAction->setMenuRole(QAction::AboutRole);
    aboutAction->setEnabled(false);
    aboutQtAction = new QAction(tr("About &Qt"), this);
    aboutQtAction->setStatusTip(tr("Show information about Qt"));
    aboutQtAction->setMenuRole(QAction::AboutQtRole);
    optionsAction = new QAction(tr("&Options..."), this);
    optionsAction->setStatusTip(tr("Modify configuration options for %1").arg(PACKAGE_NAME));
    optionsAction->setMenuRole(QAction::PreferencesRole);
    optionsAction->setEnabled(false);
    toggleHideAction = new QAction(tr("&Show / Hide"), this);
    toggleHideAction->setStatusTip(tr("Show or hide the main Window"));
    encryptWalletAction = new QAction(tr("&Encrypt Wallet..."), this);
    encryptWalletAction->setStatusTip(tr("Encrypt the private keys that belong to your wallet"));
    encryptWalletAction->setCheckable(true);
    backupWalletAction = new QAction(tr("&Backup Wallet..."), this);
    backupWalletAction->setStatusTip(tr("Backup wallet to another location"));
    changePassphraseAction = new QAction(tr("&Change Passphrase..."), this);
    changePassphraseAction->setStatusTip(tr("Change the passphrase used for wallet encryption"));
    signMessageAction = new QAction(tr("Sign &message..."), this);