TT#56343 Fix crash calculating packet stats

Backported from upstream the commits:
* 9d6356a4dfe4d455958208face87616126ca49f3
* 5e763029dc207c99796adc1c3ace71cf6de59446

Change-Id: Ie9cdb67524729d2ee8d8bf9b12e3d3a2469598bd

debian/patches/sipwise/extend_stats.patch

@@ -57,17 +57,26 @@ Subject: [PATCH] kex: Extend kamailio rcv_replies statistics
  	{0,0,0}
  };
  
-@@ -200,6 +231,28 @@ static int km_cb_req_stats(struct sip_ms
+@@ -200,6 +231,37 @@ static int km_cb_req_stats(struct sip_ms
  	return 1;
  }
  
 +static int km_cb_rpl_stats_by_method(struct sip_msg *msg,
 +		unsigned int flags, void *param)
 +{
-+      int method = get_cseq(msg)->method_id;
-+      int group = msg->first_line.u.reply.statuscode / 100 - 1;
++      int method = 0;
++      int group = 0;
 +
-+      if (group >= 1 && group <= 6) {
++      if(msg==NULL) {
++            return -1;
++      }
++      if (!msg->cseq && (parse_headers(msg, HDR_CSEQ_F, 0) < 0 || !msg->cseq)) {
++            return -1;
++      }
++      method = get_cseq(msg)->method_id;
++      group = msg->first_line.u.reply.statuscode / 100 - 1;
++
++      if (group >= 0 && group <= 5) {
 +            switch(method) {
 +                  case METHOD_INVITE: update_stat( VAR_NAME(invite)[group], 1); break;
 +                  case METHOD_CANCEL: update_stat( VAR_NAME(cancel)[group], 1); break;