app_controlplayback outputs a warning, when in fact it is normal.

(closes issue #16071)
Reported by: atis
Patches:
      controlplayback_warning.patch uploaded by atis (license 242)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@227368 65c4cc65-6c06-0410-ace0-fbb531ad65f3