fixes #653 Weird connect failures in dialer (multistress) (#660)
fixes #653 Weird connect failures in dialer (multistress) (#660)

The POLLHUP (or rather EPOLLHUP) flag does not quite mean the same
thing in Linux, and we've seen random failures where we will sometimes
get this event on a socket that is freshly connected.  This might be
a bug in Linux, but it is easy enough to workaround -- we just don't
watch for it at all.
nanomsg/nng,nanomsg/nng,nanomsg/nng,nanomsg/nng