erp5_authentication_policy: Add a log message if preference is missing.

bt5/erp5_authentication_policy/SkinTemplateItem/portal_skins/erp5_authentication_policy/Login_isLoginBlocked.py

@@ -3,6 +3,7 @@
 """
 from DateTime import DateTime
 from Products.ZSQLCatalog.SQLCatalog import Query
+from erp5.component.module.Log import log
 
 request = context.REQUEST
 portal = context.getPortalObject()
@@ -17,6 +18,13 @@ one_second = 1/24.0/60.0/60.0
 check_duration = portal_preferences.getPreferredAuthenticationFailureCheckDuration()
 block_duration = portal_preferences.getPreferredAuthenticationFailureBlockDuration()
 max_authentication_failures = portal_preferences.getPreferredMaxAuthenticationFailure()
+
+if None in (check_duration,
+            block_duration,
+            max_authentication_failures):
+  log('Login block is not working because authentication policy in system preference is not set properly.')
+  return 0
+
 check_time = now - check_duration*one_second
 
 # some failures might be still unindexed