Merge bitcoin-core/gui#189: qt: drop workaround for QTBUG-42503 which was fixed in Qt 5.5.0

a2a3f4cd8d qt: drop workaround for QTBUG-42503 which was fixed in Qt 5.5.0 (Pavol Rusnak)

Pull request description:

  Fixes https://github.com/bitcoin-core/gui/issues/101

ACKs for top commit:
  jonasschnelli:
    Tested ACK a2a3f4cd8d -

Tree-SHA512: 9ccbc20ff7991ec70cac7d4e4413f9d80a1de453e217d03927a5f167e87eae7f369f0ad437c40c8107e5384c5c5c758659ed0db923837a38f8d705f01f9cb798

src/qt/overviewpage.cpp

@@ -151,7 +151,6 @@ OverviewPage::OverviewPage(const PlatformStyle *platformStyle, QWidget *parent)
 
     // use a SingleColorIcon for the "out of sync warning" icon
     QIcon icon = platformStyle->SingleColorIcon(":/icons/warning");
-    icon.addPixmap(icon.pixmap(QSize(64,64), QIcon::Normal), QIcon::Disabled); // also set the disabled icon because we are using a disabled QPushButton to work around missing HiDPI support of QLabel (https://bugreports.qt.io/browse/QTBUG-42503)
     ui->labelTransactionsStatus->setIcon(icon);
     ui->labelWalletStatus->setIcon(icon);