CLI command logger set level auto complete.

A simple patch to enable auto tab complete.

(closes issue #17152)
Reported by: pabelanger
Patches: 
      0017152.patch uploaded by pabelanger (license 224)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@256821 65c4cc65-6c06-0410-ace0-fbb531ad65f3