QmlDesigner: even read methods need a lock

Change-Id: I7381d4c236be59ddd2015b83e9d5eb90e2cb2006
Reviewed-by: Marco Bubke <marco.bubke@digia.com>

share/qtcreator/qml/qmlpuppet/commands/valueschangedcommand.cpp

@@ -112,7 +112,9 @@ QDataStream &operator<<(QDataStream &out, const ValuesChangedCommand &command)
         QSharedMemory *sharedMemory = createSharedMemory(keyCounter, outDataStreamByteArray.size());
 
         if (sharedMemory) {
+            sharedMemory->lock();
             std::memcpy(sharedMemory->data(), outDataStreamByteArray.constData(), sharedMemory->size());
+            sharedMemory->unlock();
             out << command.keyNumber();
             return out;
         }