nua_session.c: do not clear soa when an overlapping INVITE is received

darcs-hash:20080104203122-65a35-6dadf5380d5e451e0125ed371c7571e343e9e1d8.gz

libsofia-sip-ua/nua/nua_session.c

@@ -2018,7 +2018,8 @@ int nua_invite_server_respond(nua_server_request_t *sr, tagi_t const *tags)
     reliable = 1, early_answer = 1;
   }
   else if (!nh->nh_soa || sr->sr_status >= 300) {
-    
+    if (sr->sr_neutral)
+      return nua_base_server_respond(sr, tags);
   }
   else if (tags && 100 < sr->sr_status && sr->sr_status < 200 && 
 	   !NHP_ISSET(nh->nh_prefs, early_answer)) {