tst_QNetworkReply: Don't remove file if never created

If we end up QSKIP'ing the test 'wronlyFileName' is never created.

Change-Id: I2ccbfdb630b58d7904e73b476a65a82a45ab90d7
Reviewed-by: Peter Hartmann <phartmann@blackberry.com>

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

@@ -1416,6 +1416,7 @@ void tst_QNetworkReply::initTestCase()
 void tst_QNetworkReply::cleanupTestCase()
 {
 #if !defined Q_OS_WIN
+    if (!wronlyFileName.isNull())
         QFile::remove(wronlyFileName);
 #endif
 #ifndef QT_NO_BEARERMANAGEMENT