ckpt.c:
defect 633
saCkptInitialize crashes if callbacks parameter is null

BKrev: 42b31a19Ti58H5PxsI2NaDivhyz-fQ


git-svn-id: http://svn.fedorahosted.org/svn/corosync/trunk@684 fd59a12c-fef9-0310-b244-a6a79926bd2f