use a writeable frame (some channel drivers/transcoders may modify the frame...

use a writeable frame (some channel drivers/transcoders may modify the frame after it has been passed to ast_write())


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@6926 65c4cc65-6c06-0410-ace0-fbb531ad65f3