fix(widget): do not block logout on Linux desktop environments v2

Revert commit 191fc15 to use closeEvent()
but without QEvent::ignore() which blocked logout on various Linux desktops,
and without redundant hide(). Using previous fix with hideEvent() produced
regresions because hide() is used in various places, which produced closing
behaviour.

Since qApp->setQuitOnLastWindowClosed(false) is used, and
Qt::WA_DeleteOnClose is *NOT* used, default closeEvent() handling is enough
for implementing close-to-systray feature.

Improves fix for qTox#1485 and closes qTox#3699

src/widget/widget.cpp

@@ -568,11 +568,11 @@ void Widget::moveEvent(QMoveEvent *event)
     QWidget::moveEvent(event);
 }
 
-void Widget::hideEvent(QHideEvent *event)
+void Widget::closeEvent(QCloseEvent *event)
 {
     if (Settings::getInstance().getShowSystemTray() && Settings::getInstance().getCloseToTray())
     {
-        QWidget::hideEvent(event);
+        QWidget::closeEvent(event);
     }
     else
     {
@@ -583,7 +583,7 @@ void Widget::hideEvent(QHideEvent *event)
         }
         saveWindowGeometry();
         saveSplitterGeometry();
-        QWidget::hideEvent(event);
+        QWidget::closeEvent(event);
         qApp->quit();
     }
 }

src/widget/widget.h

@@ -161,7 +161,7 @@ public slots:
 protected:
     virtual bool eventFilter(QObject *obj, QEvent *event) final override;
     virtual bool event(QEvent * e) final override;
-    virtual void hideEvent(QHideEvent *event) final override;
+    virtual void closeEvent(QCloseEvent *event) final override;
     virtual void changeEvent(QEvent *event) final override;
     virtual void resizeEvent(QResizeEvent *event) final override;
     virtual void moveEvent(QMoveEvent *event) final override;