redundant (after f28aee3ad1e6): self_update already takes care of currently active Isabelle clone;

--- a/src/Pure/Admin/isabelle_cronjob.scala	Mon May 30 22:34:45 2022 +0200
+++ b/src/Pure/Admin/isabelle_cronjob.scala	Tue May 31 12:48:12 2022 +0200
@@ -46,7 +46,6 @@
       { logger =>
         Isabelle_Devel.make_index()
 
-        Mercurial.setup_repository(Isabelle_System.isabelle_repository.root, isabelle_repos)
         Mercurial.setup_repository(Isabelle_System.afp_repository.root, afp_repos)
 
         File.write(logger.log_dir + Build_Log.log_filename("isabelle_identify", logger.start_date),