make Display Index combobox empty by default

launcher/settingsView/csettingsview_moc.cpp

@@ -57,7 +57,6 @@ void CSettingsView::setDisplayList()
 	else
 	{
 		int displayIndex = settings["video"]["displayIndex"].Integer();
-		ui->comboBoxDisplayIndex->clear();
 		ui->comboBoxDisplayIndex->addItems(list);
 		ui->comboBoxDisplayIndex->setCurrentIndex(displayIndex);
 	}

launcher/settingsView/csettingsview_moc.ui

@@ -417,13 +417,7 @@
     </widget>
    </item>
    <item row="4" column="4">
-    <widget class="QComboBox" name="comboBoxDisplayIndex">
-     <item>
-      <property name="text">
-       <string>0</string>
-      </property>
-     </item>
-    </widget>
+    <widget class="QComboBox" name="comboBoxDisplayIndex"/>
    </item>
    <item row="7" column="1" colspan="4">
     <spacer name="spacerSections">