fix minimize on close

- This code path was broken since we stopped overiding native window control

Change-Id: I77e5570faf731bc73d4b3d98f8fea9a67200fb5d
Tuleap: #276
diff --git a/mainwindow.cpp b/mainwindow.cpp
index 23fba29..edbb96e 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -32,6 +32,7 @@
 
 #include "aboutdialog.h"
 #include "mainwindowtoolbar.h"
+#include "settingskey.h"
 
 #ifdef ENABLE_AUTOUPDATE
 #include "winsparkle.h"
@@ -195,3 +196,13 @@
     else
         showMaximized();
 }
+
+void
+MainWindow::closeEvent(QCloseEvent* event)
+{
+    QSettings settings;
+    if (settings.value(SettingsKey::closeOrMinimized).toBool()) {
+        this->hide();
+        event->ignore();
+    }
+}