ckpt.c:
Fix segfault when address of checkpoint handle is null to the initialize function

BKrev: 42b319e8cJKg9zY0XT9um2oqVst5Ug


git-svn-id: http://svn.fedorahosted.org/svn/corosync/trunk@683 fd59a12c-fef9-0310-b244-a6a79926bd2f