Set cached remote endpoint immediately

* Otherwise certain abortOpen calls may not have the remote endpoint
  cached

src/Session.cxx

@@ -88,6 +88,7 @@ Session::~Session()
 void Session::asyncOpen(const std::string& localName,
     const boost::asio::ip::tcp::endpoint& remoteEndpoint)
 {
+  m_cachedRemoteEndpoint = remoteEndpoint;
   auto self = shared_from_this();
   m_strand.dispatch(
       [this, self, localName, remoteEndpoint] () {