CEL: Update unit tests for additional information

This updates the CEL unit tests for the new information contained in
the attended transfer CEL extra field.
........

Merged revisions 420513 from http://svn.asterisk.org/svn/asterisk/branches/12
........

Merged revisions 420514 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@420515 65c4cc65-6c06-0410-ace0-fbb531ad65f3