Handle EPOLLHUP and EPOLLERR from epoll explicitly
Handle EPOLLHUP and EPOLLERR from epoll explicitly

Because there no documentation that EPOLLIN and EPOLLOUT
will appear with EPOLLERR or EPOLLHUP at the same time, for safety,
we should handle EPOLLERR and EPOLLHUP explicitly.

Message-Id: <1fdc8d0420b711f6f4459cfc3b29dca27f822620@googlegroups.com>

scylladb/seastar,dreamsxin/seastar,scylladb/seastar,syuu1228/seastar,avikivity/seastar,scylladb/seastar,cloudius-systems/seastar,syuu1228/seastar,avikivity/seastar,cloudius-systems/seastar,dreamsxin/seastar,dreamsxin/seastar,avikivity/seastar,syuu1228/seastar,cloudius-systems/seastar