Issue #8592 - treat 504 as 503 (imported from 1.2)

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@48487 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -12250,6 +12250,7 @@ static void handle_response(struct sip_pvt *p, int resp, char *rest, struct sip_
 					}
 					/* Fall through */
 				case 503: /* Service Unavailable */
+				case 504: /* Server Timeout */
 					if (owner)
 						ast_queue_control(p->owner, AST_CONTROL_CONGESTION);
 					break;
@@ -12380,6 +12381,7 @@ static void handle_response(struct sip_pvt *p, int resp, char *rest, struct sip_
 				case 603: /* Decline */
 				case 500: /* Server error */
 				case 503: /* Service Unavailable */
+				case 504: /* Server timeout */
 
 					if (sipmethod == SIP_INVITE) {	/* re-invite failed */
 						sip_cancel_destroy(p);