[4108] Updated code: the sent hook gets the query

src/bin/dhcp4/dhcp4_srv.cc

@@ -718,6 +718,9 @@ Dhcpv4Srv::processPacket(Pkt4Ptr& query) {
         // Set our response
         callout_handle->setArgument("response4", rsp);
 
+        // Also pass the corresponding query packet as argument
+        callout_handle->setArgument("query4", query);
+
         // Call all installed callouts
         HooksManager::callCallouts(hook_index_pkt4_send_,
                                    *callout_handle);