MINOR: lua: use the hlua_rule type in place of opaque type
The (http|tcp)-(request|response) action rules use common
opaque type. For the HAProxy embbedded feature, types are know,
it better to add this types in the action union and use it.
diff --git a/include/types/hlua.h b/include/types/hlua.h
index 357f7ab..f481bdf 100644
--- a/include/types/hlua.h
+++ b/include/types/hlua.h
@@ -123,6 +123,7 @@
/* Empty struct for compilation compatibility */
struct hlua { };
struct hlua_socket { };
+struct hlua_rule { };
#endif /* USE_LUA */