Add an option to app_followme to disable the "please hold" announcement.

(closes issue #14155)
Reported by: junky
Patches:
      M14555-trunk.diff uploaded by junky (license 177) (modified)
Tested by: junky


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@230964 65c4cc65-6c06-0410-ace0-fbb531ad65f3