Fix a couple more Qt version issues.

- only set the clearButton on QLineEdit if we have 5.2
- use itemData/currentIndex to avoid currentData()

src/GUI/Launcher.ui

@@ -173,9 +173,6 @@
            <property name="placeholderText">
             <string>Search aircraft</string>
            </property>
-           <property name="clearButtonEnabled">
-            <bool>true</bool>
-           </property>
           </widget>
          </item>
          <item>

src/GUI/QtLauncher.cxx

@@ -675,6 +675,11 @@ QtLauncher::QtLauncher() :
     // don't require Qt 5.3
     m_ui->commandLineArgs->setPlaceholderText("--option=value --prop:/sim/name=value");
 #endif
+
+#if QT_VERSION >= 0x050200
+    m_ui->aircraftFilter->setClearButtonEnabled(true);
+#endif
+
     for (int i=0; i<4; ++i) {
         m_ratingFilters[i] = 3;
     }
@@ -933,7 +938,7 @@ void QtLauncher::onRun()
     }
 
     if (m_ui->runwayRadio->isChecked()) {
-        int index = m_ui->runwayCombo->currentData().toInt();
+        int index = m_ui->runwayCombo->itemData(m_ui->runwayCombo->currentIndex()).toInt();
         if ((index >= 0) && m_selectedAirport) {
             // explicit runway choice
             opt->addOption("runway", m_selectedAirport->getRunwayByIndex(index)->ident());