Qt4: use addCallback

modules/gui/qt4/dialogs/external.cpp

@@ -50,17 +50,15 @@ DialogHandler::DialogHandler (intf_thread_t *p_intf, QObject *_parent)
     connect (this, SIGNAL(error(const QString &, const QString &)),
              SLOT(displayError(const QString &, const QString &)));
 
-    connect (&critical, SIGNAL(pointerChanged(void *)),
-             SLOT(displayCritical(void *)),
+    critical.addCallback(this, SLOT(displayCritical(void *)),
                          Qt::BlockingQueuedConnection);
-    connect (&login, SIGNAL(pointerChanged(void *)),
-             SLOT(requestLogin(void *)),
+    login.addCallback(this, SLOT(requestLogin(void *)),
                       Qt::BlockingQueuedConnection);
-    connect (&question, SIGNAL(pointerChanged(void *)),
-             SLOT(requestAnswer(void *)),
+    question.addCallback(this, SLOT(requestAnswer(void *)),
                          Qt::BlockingQueuedConnection);
-    connect (&progressBar, SIGNAL(pointerChanged(void *)),
-             SLOT(startProgressBar(void *)),
+    question.addCallback(this, SLOT(requestAnswer(void *)),
+                         Qt::BlockingQueuedConnection);
+    progressBar.addCallback(this, SLOT(startProgressBar(void *)),
                             Qt::BlockingQueuedConnection);
     connect (this,
              SIGNAL(progressBarDestroyed(QWidget *)),