fixes sip native transfer

The Refer-To header field containing the Replaces header in the URI
was not being decoded properly.  This caused invalid parsing between
the caller id field and the domain resulting in a failed transfer.

(closes issue #17284)
Reported by: dvossel



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@261316 65c4cc65-6c06-0410-ace0-fbb531ad65f3