winrt: Removed unused member variable from socket engine

Change-Id: I3255c1fb10e053f9a9a1753ad0a0b6969d8a8cfe
Reviewed-by: David Faure <david.faure@kdab.com>

src/network/socket/qnativesocketengine_winrt_p.h

@@ -229,8 +229,6 @@ private:
     // As pendingReadOps is changed inside handleReadyRead(native callback) it has to be protected
     QMutex readOperationsMutex;
 
-    bool emitOnNewDatagram;
-
     // Protected by readMutex. Written in handleReadyRead (native callback)
     QAtomicInteger<int> bytesAvailable;