http write returns success on connection close (API Change):

fix #767

The write family of HTTP stream algorithms no longer returns
error::end_of_stream when the message indicates that the connection
should be closed.

Actions Required:

* Add code to servers to close the connection after successfully
  writing a message where `message::keep_alive()` would return `false`.

test/beast/websocket/accept.cpp

@@ -484,7 +484,7 @@ public:
         };
 
         // wrong version
-        check(http::error::end_of_stream,
+        check(error::handshake_failed,
             "GET / HTTP/1.0\r\n"
             "Host: localhost:80\r\n"
             "Upgrade: WebSocket\r\n"