5026 intra-node/inter-zone networking doesn't always deliver SIGPOLL
Reviewed by: Saso Kiselkov <skiselkov.ml@gmail.com>
Reviewed by: Gordon Ross <gordon.ross@nexenta.com>
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
Reviewed by: Robert Mustacchi <rm@joyent.com>
Approved by: Garrett D'Amore <garrett@damore.org>