Fix parsing of old settings with sdktool

With commit 5aba7fb095 the sdktool started to save id's in a QString
(instead of a QByteArray). Commit b2e3f0262b then adapted also the
parsing. However, this broke the parsing of existing settings still
using a QByteArray.

Task-number: QTCREATORBUG-14545
Change-Id: I6c991d9d130602c7e9b3146b4d7b17555056a8ef
Reviewed-by: Eike Ziller <eike.ziller@theqtcompany.com>
Reviewed-by: Tobias Hunger <tobias.hunger@theqtcompany.com>

src/tools/sdktool/addtoolchainoperation.cpp

@@ -281,6 +281,8 @@ QVariantMap AddToolChainOperation::initializeToolChains()
 bool AddToolChainOperation::exists(const QVariantMap &map, const QString &id)
 {
     QStringList valueKeys = FindValueOperation::findValue(map, id);
+    // support old settings using QByteArray for id's
+    valueKeys.append(FindValueOperation::findValue(map, id.toUtf8()));
 
     foreach (const QString &k, valueKeys) {
         if (k.endsWith(QString(QLatin1Char('/')) + QLatin1String(ID))) {