rng: Register "opened" as class property

Class properties make QOM introspection simpler and easier, as
they don't require an object to be instantiated.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20200921221045.699690-8-ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

backends/rng.c

@@ -105,10 +105,6 @@ static void rng_backend_init(Object *obj)
     RngBackend *s = RNG_BACKEND(obj);
 
     QSIMPLEQ_INIT(&s->requests);
-
-    object_property_add_bool(obj, "opened",
-                             rng_backend_prop_get_opened,
-                             rng_backend_prop_set_opened);
 }
 
 static void rng_backend_finalize(Object *obj)
@@ -123,6 +119,10 @@ static void rng_backend_class_init(ObjectClass *oc, void *data)
     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
 
     ucc->complete = rng_backend_complete;
+
+    object_class_property_add_bool(oc, "opened",
+                                   rng_backend_prop_get_opened,
+                                   rng_backend_prop_set_opened);
 }
 
 static const TypeInfo rng_backend_info = {