SOUP_IS_MESSAGE_FILTER_CLASS produces wrong code

[cascardo minaslivre org]

Simple fix for a macro that is not yet used in the core code.

--- soup-message-filter.h.old	2007-05-24 17:49:25.000000000 -0300
+++ soup-message-filter.h	2007-05-24 17:49:36.000000000 -0300
@@ -12,7 +12,7 @@
 #define SOUP_MESSAGE_FILTER(obj)            (G_TYPE_CHECK_INSTANCE_CAST ((obj), SOUP_TYPE_MESSAGE_FILTER, SoupMessageFilter))
 #define SOUP_MESSAGE_FILTER_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST ((klass), SOUP_TYPE_MESSAGE_FILTER, SoupMessageFilterClass))
 #define SOUP_IS_MESSAGE_FILTER(obj)         (G_TYPE_CHECK_INSTANCE_TYPE ((obj), SOUP_TYPE_MESSAGE_FILTER))
-#define SOUP_IS_MESSAGE_FILTER_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((obj), SOUP_TYPE_MESSAGE_FILTER))
+#define SOUP_IS_MESSAGE_FILTER_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), SOUP_TYPE_MESSAGE_FILTER))
 #define SOUP_MESSAGE_FILTER_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_INTERFACE ((obj), SOUP_TYPE_MESSAGE_FILTER, SoupMessageFilterClass))
 
 typedef struct {