QNAM: Fix double-connect for manual redirect handling

The other signal connections are broken because we create a new
delegate. But 'q' is still the same, so we should not connect to
it a second time.
Just connect it in the constructor instead.

Fixes: QDS-9687
Pick-to: 6.5 6.2 5.15
Change-Id: Id47492c2e734087281a3d3488649471814fd981d
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

src/network/access/qnetworkreplyhttpimpl.cpp

@@ -154,6 +154,9 @@ QNetworkReplyHttpImpl::QNetworkReplyHttpImpl(QNetworkAccessManager* const manage
         d->sslConfiguration.reset(new QSslConfiguration(request.sslConfiguration()));
 #endif
 
+    QObjectPrivate::connect(this, &QNetworkReplyHttpImpl::redirectAllowed, d,
+            &QNetworkReplyHttpImplPrivate::followRedirect, Qt::QueuedConnection);
+
     // FIXME Later maybe set to Unbuffered, especially if it is zerocopy or from cache?
     QIODevice::open(QIODevice::ReadOnly);
 
@@ -870,9 +873,6 @@ void QNetworkReplyHttpImplPrivate::postRequest(const QNetworkRequest &newHttpReq
                 q, SLOT(onRedirected(QUrl,int,int)),
                 Qt::QueuedConnection);
 
-        QObject::connect(q, SIGNAL(redirectAllowed()), q, SLOT(followRedirect()),
-                         Qt::QueuedConnection);
-
 #ifndef QT_NO_SSL
         QObject::connect(delegate, SIGNAL(sslConfigurationChanged(QSslConfiguration)),
                 q, SLOT(replySslConfigurationChanged(QSslConfiguration)),