[libpeas] Warn if we fail to find the method in introspection.

[Steve Frécinaux <sfre src gnome org>]

commit f50347cc5a977403a3e8bed4436e6ec4a5a2d589
Author: Garrett Regier <alias301 gmail com>
Date:   Wed Dec 15 08:21:14 2010 -0800

    Warn if we fail to find the method in introspection.
    
    We were failing silently. This made troubleshooting harder.

 libpeas/peas-extension.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)
---
diff --git a/libpeas/peas-extension.c b/libpeas/peas-extension.c
index 68558d1..21cd538 100644
--- a/libpeas/peas-extension.c
+++ b/libpeas/peas-extension.c
@@ -223,8 +223,7 @@ peas_extension_call_valist (PeasExtension *exten,
   g_return_val_if_fail (method_name != NULL, FALSE);
 
   callable_info = peas_gi_get_method_info (exten->priv->exten_type, method_name);
-  if (callable_info == NULL)
-    return FALSE;
+  g_return_val_if_fail (callable_info != NULL, FALSE);
 
   n_args = g_callable_info_get_n_args (callable_info);
   g_return_val_if_fail (n_args >= 0, FALSE);