configs/agents.conf.sample - Remove example for non-functional "goodbye" parameter

The "goodbye" parameter is not implemented in the source code, it does nothing.

(closes issue SWP-6518)
Reported By: Steve Pitts
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Merged revisions 408020 from http://svn.asterisk.org/svn/asterisk/branches/1.8


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/11@408021 65c4cc65-6c06-0410-ace0-fbb531ad65f3