Fix regression in Socket::shutdown() when having _noShutdown set

Regression injected with commit 0579ee81c709865ea420c2d70dcc443bdf69de1a
of PR CollaboraOnline/online#9916

Original behavior was to do nothing in Socket::shutdown(),
while the commit in question did setClosed() leading
to an eventual socket close within SocketPoll::poll().

The latter causes an error within system ::ppoll().

Signed-off-by: Sven Göthel <[email protected]>
Change-Id: I57d46e0428905137e05d34dad450fea1d6a0f127

net/Socket.hpp

@@ -217,10 +217,10 @@ class Socket
     /// TODO: Support separate read/write shutdown.
     virtual void shutdown()
     {
-        setClosed();
         if (!_noShutdown)
         {
             LOG_TRC("Socket shutdown RDWR. " << *this);
+            setClosed();
             if constexpr (!Util::isMobileApp())
                 ::shutdown(_fd, SHUT_RDWR);
             else