authn: Remove usage of colander.serialize to generate form defaults.

rhodecode/authentication/views.py

@@ -59,10 +59,9 b' class AuthnPluginViewBase(object):'
         # Compute default values for the form. Priority is:
         # 1. Passed to this method 2. DB value 3. Schema default
         for node in schema:
-            db_value = self.plugin.get_setting_by_name(
-                node.name, colander.null)
-            defaults.setdefault(node.name, db_value)
-        defaults = schema.serialize(defaults)
+            value = self.plugin.get_setting_by_name(
+                node.name, node.default)
+            defaults.setdefault(node.name, value)
 
         template_context = {
             'defaults': defaults,