Cleanup event on exit.

* Cleanup CLI commands on exit.

(issue ASTERISK-20649)
Reported by: Corey Farrell
Patches:
      event_shutdown-10-only.patch (license #5909) patch uploaded by Corey Farrell
      event_shutdown-1_8-11-trunk.patch (license #5909) patch uploaded by Corey Farrell
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Merged revisions 377708 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 377709 from http://svn.asterisk.org/svn/asterisk/branches/10
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Merged revisions 377710 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@377711 65c4cc65-6c06-0410-ace0-fbb531ad65f3