Merged revisions 208587 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.4

........
  r208587 | mmichelson | 2009-07-24 13:26:50 -0500 (Fri, 24 Jul 2009) | 10 lines
  
  Only send a BYE when hanging up a channel that is up.
  
  For cases where Asterisk sends an INVITE and receives a non 2XX final
  response, Asterisk would follow the INVITE transaction by immediately
  sending a BYE, which was unnecessary.
  
  (closes issue #14575)
  Reported by: chris-mac
........


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@208588 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -6060,7 +6060,9 @@ static int sip_hangup(struct ast_channel *ast)
 				}
 
 				/* Send a hangup */
-				transmit_request_with_auth(p, SIP_BYE, 0, XMIT_RELIABLE, 1);
+				if (oldowner->_state == AST_STATE_UP) {
+					transmit_request_with_auth(p, SIP_BYE, 0, XMIT_RELIABLE, 1);
+				}
 
 			} else {
 				/* Note we will need a BYE when this all settles out