schema source: avoid introspection confusion

Any method that has its prefix'd argument as its first parameter will be
interpreted by introspection as a method. We don't want this, so we need
to swap the first two parameters.

gio/gsettingsschema.c

@@ -95,8 +95,8 @@ g_settings_schema_source_unref (GSettingsSchemaSource *source)
 }
 
 GSettingsSchemaSource *
-g_settings_schema_source_new_from_directory (GSettingsSchemaSource  *parent,
-                                             const gchar            *directory,
+g_settings_schema_source_new_from_directory (const gchar            *directory,
+                                             GSettingsSchemaSource  *parent,
                                              gboolean                trusted,
                                              GError                **error)
 {