fixed a warning

git-svn-id: file:///home/svn/mapi/trunk@873 8d5bb341-7cf1-0310-8cf6-ba355fef3186

src/extraflib/topx.c

@@ -550,7 +550,7 @@ static int topx_process(mapidflib_function_instance_t *instance,
 
 static int topx_instance(mapidflib_function_instance_t *instance,
 			     MAPI_UNUSED int flow_descr,
-			     mapidflib_flow_mod_t *flow_mod)
+			     MAPI_UNUSED mapidflib_flow_mod_t *flow_mod)
 {
 	mapiFunctArg *fargs = instance->args;