Change chan_skinny to use debug messages as appropriate.

(closes issue #11967)
Reported by: mvanbaak
Patches:
      2008021000-skinnydebug.diff.txt uploaded by mvanbaak (license 7)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@103313 65c4cc65-6c06-0410-ace0-fbb531ad65f3