This fixes a problem where MWI FSK spills were being injected onto off hook fxs lines.

(closes issue #14143)
Reported by: alecdavis
Patches:
      chan_dahdi-14143.patch.txt uploaded by dbailey (license )
Tested by: alecdavis



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@168619 65c4cc65-6c06-0410-ace0-fbb531ad65f3