QHelpEngineCore::setReadOnly does not close the connection

setReadOnly does not close the connection to the database which makes for example a case like this not working:

setupData()
setReadOnly(false)
setupData()

The second setupData() does nothing as there is a check like this where m_query already exists from the first call:

bool QHelpCollectionHandler::openCollectionFile()
{
if (m_query)
return true;