Handle the POLLRDHUP poll(2) revent
Handle the POLLRDHUP poll(2) revent

This commit adds some code to handle the POLLRDHUP revent returned by
poll(2), to detect unreadable sockets early on.

Change-Id: If4fd8f829ff890c0a7551086353ce317325d493e
See: d244306899be624b003a80f799efac31569604b1
See: ARAKOON-324
See: http://jira.incubaid.com/browse/ARAKOON-324
(cherry picked from commit 0d8ab239110240076f7e0e38efba49f6aa8aea5e)

Incubaid/crakoon,Incubaid/crakoon,Incubaid/crakoon,Incubaid/crakoon