QTemporaryFileEngine now tracks if a fileName has been generated
QTemporaryFileEngine now tracks if a fileName has been generated

With recent changes to QTemporaryFile, allowing the file to be closed,
the engine has to keep track of whether a fileName has already been
generated, so we don't generate new files after the first one.

If the file is closed but we already have a name for it, then just
forward the call to the base file engine.

Reviewed-by: Thiago

pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,radekp/qt,RLovelett/qt,radekp/qt,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,RLovelett/qt,RLovelett/qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,radekp/qt,RLovelett/qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,igor-sfdc/qt-wk,RLovelett/qt,radekp/qt,igor-sfdc/qt-wk,radekp/qt,KDE/qt,pruiz/wkhtmltopdf-qt,KDE/qt,KDE/qt,RLovelett/qt,RLovelett/qt,KDE/qt,KDE/qt,RLovelett/qt,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,igor-sfdc/qt-wk,radekp/qt,igor-sfdc/qt-wk,radekp/qt,radekp/qt,pruiz/wkhtmltopdf-qt,pruiz/wkhtmltopdf-qt,radekp/qt,KDE/qt,RLovelett/qt,RLovelett/qt,KDE/qt,igor-sfdc/qt-wk,igor-sfdc/qt-wk,pruiz/wkhtmltopdf-qt,RLovelett/qt,KDE/qt,radekp/qt,igor-sfdc/qt-wk