fix duplicate address detection (ARMmbed#1760)

Author: Mika Tervonen

source/6LoWPAN/Thread/thread_extension_bbr.c

@@ -546,7 +546,7 @@ static int thread_pbbr_dua_duplicate_address_detection(int8_t service_id, uint8_
     }
 
     // We have pending request and received answer
-    if (memcmp(ml_eid_ptr,tr_ptr->ml_eid, 8) != 0 && memcmp(addr_data_ptr, tr_ptr->source_address, 16) == 0){
+    if (memcmp(ml_eid_ptr,tr_ptr->ml_eid, 8) != 0) {
         // Different ml_eid but same address means duplicate address detected
         thread_resolution_client_address_error(this->interface_id, tr_ptr->source_address, tr_ptr->target_eid, tr_ptr->ml_eid);
         ipv6_neighbour_t *neighbour_entry;
@@ -556,6 +556,7 @@ static int thread_pbbr_dua_duplicate_address_detection(int8_t service_id, uint8_
             ipv6_neighbour_entry_remove(&cur->ipv6_neighbour_cache, neighbour_entry);
         }
         ipv6_route_delete(route->prefix, route->prefix_len, this->interface_id, NULL, ROUTE_THREAD_PROXIED_DUA_HOST);
+        thread_border_router_dup_tr_delete(tr_ptr);
     }
 
     return 0;