Qt: fix mem leaks in screenshot and save managers

rpcs3/rpcs3qt/save_manager_dialog.cpp

@@ -98,6 +98,7 @@ save_manager_dialog::save_manager_dialog(std::shared_ptr<gui_settings> gui_setti
 {
 	setWindowTitle(tr("Save Manager"));
 	setMinimumSize(QSize(400, 400));
+	setAttribute(Qt::WA_DeleteOnClose);
 
 	Init(dir);
 }

rpcs3/rpcs3qt/screenshot_manager_dialog.cpp

@@ -15,6 +15,7 @@
 screenshot_manager_dialog::screenshot_manager_dialog(QWidget* parent) : QDialog(parent)
 {
 	setWindowTitle(tr("Screenshots"));
+	setAttribute(Qt::WA_DeleteOnClose);
 
 	m_icon_size = QSize(160, 90);