Fixup redirection after request an instance

See merge request !529
3 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
failed SlapOS-Master.UnitTest-Master

02:43:06

passed SlapOS.Eggs.UnitTest-Master.Python2

00:14:05

passed SlapOS.Eggs.UnitTest-Master.Python3

00:17:20