Fix crash.

Check if there is any qtVersion->qtAbis() before getting the first element.

Change-Id: Ia55985b513cc2473dd0cfbef45877185d65df6ef
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/plugins/android/androidsettingswidget.cpp

@@ -241,7 +241,7 @@ bool AndroidSettingsWidget::checkNDK(const Utils::FileName &location)
 
     QSet<ProjectExplorer::Abi::Architecture> qtVersionsForArch;
     foreach (QtSupport::BaseQtVersion *qtVersion, QtSupport::QtVersionManager::instance()->versions()) {
-        if (qtVersion->type() != QLatin1String(Constants::ANDROIDQT))
+        if (qtVersion->type() != QLatin1String(Constants::ANDROIDQT) || qtVersion->qtAbis().isEmpty())
             continue;
         qtVersionsForArch.insert(qtVersion->qtAbis().first().architecture());
     }