add CHANNEL_HANGUP_COMPLETE event to take the place of CHANNEL_HANGUP, CHANNEL_HANGUP now fires as soon as the channel is hungup but you must wait for CHANNEL_HANGUP_COMPLETE for the CDR data

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@13505 d0543943-73ff-0310-b7d9-9358b9ac24b2