HTTP/2: fixed socket leak with queued frames (ticket #1689). If a stream is closed with queued frames, it is possible that no further write events will occur on the stream, leading to the socket leak. To fix this, the stream's fake connection read handler is set to ngx_http_v2_close_stream_handler(), to make sure that finalizing the connection with ngx_http_v2_finalize_connection() will be able to close the stream regardless of the current number of queued frames. Additionally, the stream's fake connection fc->error flag is explicitly set, so ngx_http_v2_handle_stream() will post a write event when queued frames are finally sent even if stream flow control window is exhausted.