Remove extraneous BRIDGEPEER AMI VarSet event on a CEL dummy channel.

(closes issue ASTERISK-19180)
Reported by: Corey Farrell
Patches:
      asterisk_cel_noevent_varset.diff (license #5909) patch uploaded by Corey Farrell
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Merged revisions 350452 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 350453 from http://svn.asterisk.org/svn/asterisk/branches/10


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@350454 65c4cc65-6c06-0410-ace0-fbb531ad65f3