Send DialPlanComplete as a response, not as a separate event.

Otherwise, it goes to all manager sessions and may exclude the current session,
if the Events mask excludes it.

(closes issue #17504)
 Reported by: rrb3942
 Patches: 
       showdialplan_patch.diff uploaded by rrb3942 (license 1003)
 Tested by: rrb3942


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@273054 65c4cc65-6c06-0410-ace0-fbb531ad65f3