possibility to absent public key from server

PROD-17856

Change-Id: Ife3cf46e786db6252d332f69c69389e4b5aa587a
diff --git a/backupninja/server.sls b/backupninja/server.sls
index 3a96c3d..7417b45 100644
--- a/backupninja/server.sls
+++ b/backupninja/server.sls
@@ -51,6 +51,13 @@
   - require:
     - file: {{ server.home_dir }}
 
+{%- else %}
+
+backupninja_key_{{ key.key }}:
+  ssh_auth.absent:
+  - user: backupninja
+  - name: {{ key.key }}
+
 {%- endif %}
 
 {%- endfor %}