res_musiconhold.c: Remove obsolete REF_DEBUG code.

Remove unneeded code that writes to the wrong file location in an obsolete
format.
........

Merged revisions 421799 from http://svn.asterisk.org/svn/asterisk/branches/1.8


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/11@421800 65c4cc65-6c06-0410-ace0-fbb531ad65f3