Cork the proper output stream in the client

The socket might not be the stream actually used, e.g. when we are using
TLS. Make sure we cork the proper stream to get all the benefits of
corking.

vncviewer/CConn.cxx

@@ -247,7 +247,7 @@ void CConn::socketEvent(FL_SOCKET fd, void *data)
     // We might have been called to flush unwritten socket data
     cc->sock->outStream().flush();
 
-    cc->sock->outStream().cork(true);
+    cc->getOutStream()->cork(true);
 
     // processMsg() only processes one message, so we need to loop
     // until the buffers are empty or things will stall.
@@ -263,7 +263,7 @@ void CConn::socketEvent(FL_SOCKET fd, void *data)
         break;
     }
 
-    cc->sock->outStream().cork(false);
+    cc->getOutStream()->cork(false);
   } catch (rdr::EndOfStream& e) {
     vlog.info("%s", e.str());
     if (!cc->desktop) {