Address standalone kubelet config case

Also place in global vars and do not repeat the kube_*_config_dir
and kube_namespace vars for better code maintainability and UX.

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

roles/reset/tasks/main.yml

@@ -34,7 +34,7 @@
 - name: reset | delete some files and directories
   file: path={{ item }} state=absent
   with_items:
-    - /etc/kubernetes/
+    - "{{kube_config_dir}}"
     - /var/lib/kubelet
     - /var/lib/etcd
     - /etc/ssl/etcd