Do not double-delete the TCP socket of a QWebSocket.

Do not double-delete the TCP socket of a QWebSocket.

The socket is put into an owning QScopedPointer. But if its also
put into the QObject parent-child chain, it will get deleted when
the QWebSocket is destroyed. In the dtor of the QWebSocketPrivate
class m_pSocket will thus already be destroyed and thus be a
dangling pointer.

This crashed the QWebSocketServer test reliably for me on exit.

Change-Id: I7f06e933bfed832e66b943542c351cde639c9465
Reviewed-by: Kurt Pattyn <pattyn.kurt@gmail.com>