epoll_wait collects revent by checking fds->revent,
but local_socket will copy fds to the other two private pollfd shandow struct,
then the pipe_poll will not be able to update fds->revent directly,
so need local_socket save fds and implement a private poll_notify function
to passing revent to original fds->revent.
Signed-off-by: zhanghongyu <zhanghongyu@xiaomi.com>