Add handler for channel open async and add a test to
testevt for the async channel open function.
Bug fix for event retention time clear exec code and added comments
when converting nanoseconds to milliseconds.

BKrev: 4208f4048DxJP7FLwfqHo7TfAoEJlA


git-svn-id: http://svn.fedorahosted.org/svn/corosync/trunk@477 fd59a12c-fef9-0310-b244-a6a79926bd2f