Make sure "configure" pages use AppHandler to save/delete settings

so that beaker config cache is invalidated, if in use

tailbone/views/batch/vendorcatalog.py

@@ -436,15 +436,18 @@ class VendorCatalogView(FileBatchMasterView):
 
     def configure_remove_settings(self):
         super(VendorCatalogView, self).configure_remove_settings()
-        model = self.model
+        app = self.get_rattail_app()
+
         names = [
             'rattail.vendors.supported_catalog_parsers',
             'tailbone.batch.vendorcatalog.supported_parsers', # deprecated
         ]
 
-        Session().query(model.Setting)\
-                 .filter(model.Setting.name.in_(names))\
-                 .delete(synchronize_session=False)
+        # nb. using thread-local session here; we do not use
+        # self.Session b/c it may not point to Rattail
+        session = Session()
+        for name in names:
+            app.delete_setting(session, name)
 
 
 # TODO: deprecate / remove this