Remove unused variable from QNetworkReply benchmark

Fixes compiler warning.

Change-Id: I73963f9f711b02d999b366dbf884acd5c851c950
Reviewed-by: Andreas Buhr <andreas.buhr@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

tests/benchmarks/network/access/qnetworkreply/tst_qnetworkreply.cpp

@@ -163,7 +163,6 @@ class ThreadedDataReader: public QThread
     // used to make the constructor only return after the tcp server started listening
     QSemaphore ready;
     QTcpSocket *client;
-    int timeout;
     int port;
 public:
     qint64 transferRate;