reverses incorrect logic introduced by r243200

The decoding of the replace_id did not need to be broken
up in this instance.  This was brought to my attention
again because it caused a segfault when the from or to
tags were not present in the "Replaces" header.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@265366 65c4cc65-6c06-0410-ace0-fbb531ad65f3