update sample to reflect new nodir option

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@6058 65c4cc65-6c06-0410-ace0-fbb531ad65f3

configs/musiconhold.conf.sample

@@ -9,6 +9,8 @@ default => quietmp3:/var/lib/asterisk/mohmp3
 ;quietunbuf => quietmp3nb:/var/lib/asterisk/mohmp3
 ; Note that the custom mode cannot handle escaped parameters (specifically embedded spaces)
 ;manual => custom:/var/lib/asterisk/mohmp3,/usr/bin/mpg123 -q -r 8000 -f 8192 -b 2048 --mono -s
+; For a custom app, reading from a directory may not be necessary
+;manual => custom:nodir,/bin/my-dirless-app myarg
 
 ;
 ; File-based (native) music on hold