Importing rev 45196 from 1.4 - don't kill dialog for a bad response

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@45204 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -11514,10 +11514,8 @@ static void handle_response_invite(struct sip_pvt *p, int resp, char *rest, stru
 static void handle_response_refer(struct sip_pvt *p, int resp, char *rest, struct sip_request *req, int seqno)
 {
 	/* If no refer structure exists, then do nothing */
-	if (!p->refer) {
-		ast_set_flag(&p->flags[0], SIP_NEEDDESTROY);
+	if (!p->refer)
 		return;
-	}
 
 	switch (resp) {
 	case 202:   /* Transfer accepted */