Based on the following patch, changed for trunk...

Merged revisions 50124 via svnmerge from 
https://origsvn.digium.com/svn/asterisk/branches/1.4

........
r50124 | oej | 2007-01-09 12:25:20 +0100 (Tue, 09 Jan 2007) | 3 lines

- handle re-invites properly in sip_hangup()
- Add some invitestate status changes just to be sure

........


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@50132 65c4cc65-6c06-0410-ace0-fbb531ad65f3