SSL: fixed event handling during shutdown.

The c->read->ready and c->write->ready flags need to be cleared to ensure
that appropriate read or write events will be reported by kernel.  Without
this, SSL shutdown might wait till the timeout after blocking on writing
or reading even if there is a socket activity.

src/event/ngx_event_openssl.c

@@ -2865,6 +2865,13 @@ ngx_ssl_shutdown(ngx_connection_t *c)
             c->read->handler = ngx_ssl_shutdown_handler;
             c->write->handler = ngx_ssl_shutdown_handler;
 
+            if (sslerr == SSL_ERROR_WANT_READ) {
+                c->read->ready = 0;
+
+            } else {
+                c->write->ready = 0;
+            }
+
             if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
                 return NGX_ERROR;
             }