erp5_hal_json_style Base_redirect: Remove dead code

Nothing uses redirect_url, so do not bother setting it.
6 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
failed ERP5.CodingStyleTest-Master

01:00:47

failed ERP5.UnitTest-Master

01:35:58

passed ERP5.UnitTest-Zope2

01:23:55

passed SlapOS.Eggs.UnitTest-Master.Python2

00:14:11

passed SlapOS.Eggs.UnitTest-Master.Python3

00:17:48

failed Wendelin.UnitTest-Master

00:41:06