[core] skip interest in POLLRDHUP after POLLRDHUP (#3059)
[core] skip interest in POLLRDHUP after POLLRDHUP (#3059)

x-ref:
  "Connections stuck in Close_Wait causing 100% cpu usage"
  https://redmine.lighttpd.net/issues/3059

gstrauss/lighttpd1.4,lighttpd/lighttpd1.4,lighttpd/lighttpd1.4,gstrauss/lighttpd1.4,gstrauss/lighttpd1.4,lighttpd/lighttpd1.4,gstrauss/lighttpd1.4,lighttpd/lighttpd1.4,gstrauss/lighttpd1.4,lighttpd/lighttpd1.4,gstrauss/lighttpd1.4,lighttpd/lighttpd1.4