QNativeSocketEngine: use stream-style qDebug to fix a warning about FD types.

FD types differ depending on the platform, so using the stream form is the
easiest way to make this work.

Change-Id: I00b1a303f3d865fe5e89ba97bd438c51c6cd8f09
Reviewed-by: Richard J. Moore <rich@kde.org>

src/network/socket/qnativesocketengine.cpp

@@ -430,8 +430,8 @@ bool QNativeSocketEngine::initialize(qintptr socketDescriptor, QAbstractSocket::
     // determine socket type and protocol
     if (!d->fetchConnectionParameters()) {
 #if defined (QNATIVESOCKETENGINE_DEBUG)
-        qDebug("QNativeSocketEngine::initialize(socketDescriptor == %i) failed: %s",
-               socketDescriptor, d->socketErrorString.toLatin1().constData());
+        qDebug() << "QNativeSocketEngine::initialize(socketDescriptor) failed:"
+                 << socketDescriptor << d->socketErrorString;
 #endif
         d->socketDescriptor = -1;
         return false;