* fixed a nasty bug in epoll_loop() and poll_loop() by which an EPOLL_HUP event

* fixed a nasty bug in epoll_loop() and poll_loop() by which an EPOLL_HUP event
  could trigger both a read and a write calls, thus sometimes inducing headers
  being directly sent from srv to cli without modification, and leading further
  modification to crash the process by memory corruption, because
  rep.data+rep.l<rep.h so the memmove() length argument is negative. Only
  observed with epoll() and never poll(), though this one should have been
  affected too. Now, only call functions which have been allowed to.