Handle POLLNVAL in coroipcc
Old code in coroipcc doesn't handle POLLNVAL. It can happen, that some
applications (for example fenced) will stuck forever.
Also poll result is now handled more correctly.
git-svn-id: http://svn.fedorahosted.org/svn/corosync/trunk@2789 fd59a12c-fef9-0310-b244-a6a79926bd2f