does not know what to do with these alarms. Only Asterisk 1.6 cares about it.
So, if we get an unknown alarm in chan_zap, don't generate confusing log messages
about it.
git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@104332 65c4cc65-6c06-0410-ace0-fbb531ad65f3