[libpeas] Be more strict in peas_object_module_register_extension_type()

[Garrett Regier <gregier src gnome org>]

commit f6dac8247dad2a8f684c9598cf1a454fba7ee902
Author: Garrett Regier <garrettregier gmail com>
Date:   Fri Nov 20 02:44:09 2015 -0800

    Be more strict in peas_object_module_register_extension_type()
    
    Before it was possible to specify that the iface_type
    was that of PeasPluginLoader and bypass the check
    that the extensin type is of the iface_type.

 libpeas/peas-object-module.c |    6 ++----
 1 files changed, 2 insertions(+), 4 deletions(-)
---
diff --git a/libpeas/peas-object-module.c b/libpeas/peas-object-module.c
index fb6f975..68cb43a 100644
--- a/libpeas/peas-object-module.c
+++ b/libpeas/peas-object-module.c
@@ -564,12 +564,10 @@ peas_object_module_register_extension_type (PeasObjectModule *module,
 {
   g_return_if_fail (PEAS_IS_OBJECT_MODULE (module));
   g_return_if_fail (!peas_object_module_provides_object (module, iface_type));
+  g_return_if_fail (g_type_is_a (extension_type, iface_type));
 
   if (iface_type != PEAS_TYPE_PLUGIN_LOADER)
-    {
-      g_return_if_fail (G_TYPE_IS_INTERFACE (iface_type));
-      g_return_if_fail (g_type_is_a (extension_type, iface_type));
-    }
+    g_return_if_fail (G_TYPE_IS_INTERFACE (iface_type));
 
   peas_object_module_register_extension_factory (module,
                                                  iface_type,