temporary hack to avoid segfaults on 503 w/ retry-after and 423 responses to…

temporary hack to avoid segfaults on 503 w/ retry-after and 423 responses to CANCEL (and maybe others) (SFSIP-134)

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@12942 d0543943-73ff-0310-b7d9-9358b9ac24b2

libs/sofia-sip/libsofia-sip-ua/nua/nua_client.c

@@ -1140,7 +1140,7 @@ int nua_base_client_check_restart(nua_client_request_t *cr,
   if (status == 423) {
     unsigned my_expires = 0;
 
-    if (cr->cr_sip->sip_expires)
+    if (cr->cr_sip && cr->cr_sip->sip_expires)
       my_expires = cr->cr_sip->sip_expires->ex_delta;
 
     if (sip->sip_min_expires &&
@@ -1195,7 +1195,8 @@ int nua_base_client_check_restart(nua_client_request_t *cr,
     }
   }
 
-  if (0 && 500 <= status && status < 600 &&
+  if (500 <= status && status < 600 &&
+	  cr->cr_sip &&
       sip->sip_retry_after &&
       sip->sip_retry_after->af_delta < 32) {
     su_timer_t *timer;