marsadm: prevent mutual overwrite of delete symlinks

Add an (unused) host context. Previously, concurrent
log-delete operations triggered by cron could lead to
unnecessary loss of deletetion symlinks.

kernel/sy_old/mars_light.c

@@ -3918,6 +3918,7 @@ static const struct light_class light_classes[] = {
 		.cl_len = 7,
 		.cl_type = 'l',
 		.cl_serial = true,
+		.cl_hostcontext = false, // ignore context, although present
 		.cl_father = CL_GLOBAL_TODO,
 		.cl_prepare = prepare_delete,
 	},

userspace/marsadm

@@ -1091,7 +1091,7 @@ sub _create_delete {
       }
     }
   }
-  my $new = sprintf("$mars/todo-global/delete-%09d", ++$delete_nr);
+  my $new = sprintf("$mars/todo-global/delete-%09d-$host", ++$delete_nr);
   lprint "create symlink $new -> $target\n";
   set_link($target, $new);
 }