main.c:
Call poll_destroy when executing ais_done. This increases code
coverage from 66.9% to 82.3%.

BKrev: 4148ac12oFAraidHBF8lhdpMgBXc1w


git-svn-id: http://svn.fedorahosted.org/svn/corosync/trunk@256 fd59a12c-fef9-0310-b244-a6a79926bd2f