Print/Page setup dialogs leak

This may affect other platforms, or may be specific to the Mac sheet implementation.

If a QPrintDialog/QPageSetupDialog dialog has the Qt::WA_DeleteOnClose attribute set to true, closing the dialog does perform the normal "delete later" setup (e.g., QAbstractPageSetupDialog::done calls QWidgetPrivate::close_helper, which calls deleteLater to schedule the object for deletion).

However the object is never actually deleted, even after control returns to the event loop, and the dialog is leaked.

This can be seen by subclassing one of these dialogs, emitting a log message in the destructor, then opening/closing the dialog.