Fix setting CDR variables in the hangup extension

A previous CDR fix for setting CDR variables during a bridge via
custom dialplan features broke setting CDR variables in the
hangup extension. This patch fixes the issue.

Review: https://reviewboard.asterisk.org/r/1794/
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Merged revisions 358978 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 358989 from http://svn.asterisk.org/svn/asterisk/branches/10


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@358993 65c4cc65-6c06-0410-ace0-fbb531ad65f3