make absent_users default to empty list

defaults/main.yml

@@ -7,5 +7,4 @@ human_users:
   #   ssh_key_file: "claussni.pub"
   #   ssh_key_url: https://git.slub-dresden.de/{{ name }}.keys
 
-absent_users:
-  # - "dummy"
\ No newline at end of file
+absent_users: []
\ No newline at end of file

tasks/main.yml

@@ -48,7 +48,6 @@
     force: true
     remove: true
   with_items: "{{ absent_users }}"
-  ignore_errors: true
   become: true
 
 - name: Authorize personal SSH keys from file