Don't allow for configuration options to overwrite options

set via channel variables on a reload.

(closes issue #13921)
Reported by: davidw
Patches:
      13921.patch uploaded by putnopvut (license 60)
Tested by: davidw



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@159437 65c4cc65-6c06-0410-ace0-fbb531ad65f3