Merged revisions 327211 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.8

........
  r327211 | rmudgett | 2011-07-08 16:41:58 -0500 (Fri, 08 Jul 2011) | 9 lines
  
  INVITE 403 Forbidden response always retransmits the maximum times.
  
  Asterisk sends a 403 Forbidden response if authentication fails for an
  INVITE as required.  However, it ignores the ACK and keeps retransmitting
  the response.
  
  * Made not delete the to-tag in the dialog so the expected ACK can be
  matched with the dialog and stop the retransmissions.
........


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@327212 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -22523,7 +22523,6 @@ static int handle_request_invite(struct sip_pvt *p, struct sip_request *req, int
 			}
 			p->invitestate = INV_COMPLETED;
 			sip_scheddestroy(p, DEFAULT_TRANS_TIMEOUT);
-			ast_string_field_set(p, theirtag, NULL);
 			res = 0;
 			goto request_invite_cleanup;
 		}