Deadlock when closing connection when TLS was never established (caused by 268f6355)

Source commit: 24d6adda3af26be8871a9973338011cfe8d0c86c

source/filezilla/AsyncSslSocketLayer.cpp

@@ -606,7 +606,7 @@ int CAsyncSslSocketLayer::Receive(void* lpBuf, int nBufLen, int nFlags)
 
 void CAsyncSslSocketLayer::Close()
 {
-  if (!m_nShutDown)
+  if (!m_nShutDown && m_bSslEstablished)
   {
     ShutDown();
     while (!ShutDownComplete())