Bail out if we have no refer structure and we get a refer response

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@44806 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -11539,6 +11539,12 @@ static void handle_response_refer(struct sip_pvt *p, int resp, char *rest, struc
 	char *auth = "Proxy-Authenticate";
 	char *auth2 = "Proxy-Authorization";
 
+	/* If no refer structure exists, then do nothing */
+	if (!p->refer) {
+		ast_set_flag(&p->flags[0], SIP_NEEDDESTROY);
+		return;
+	}
+
 	switch (resp) {
 	case 202:   /* Transfer accepted */
 		/* We need  to do something here */