Send a manager AgentComplete event when the agent transfers the call, in

addition to where it is already sent if either side hangs up.
(issue #9219, rgollent)
In passing, I put this code in a function so it would not be duplicated
a third time.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@58123 65c4cc65-6c06-0410-ace0-fbb531ad65f3