harden reset to work in more cases (#6781)

reset playbook fails and does not continue cleanup after for
example a host reboot with kubelet stopped/disabled

roles/reset/tasks/main.yml

@@ -147,6 +147,7 @@
     warn: false
   check_mode: no
   register: mounted_dirs
+  failed_when: false
   tags:
     - mounts
 
@@ -154,6 +155,7 @@
   command: umount -f {{ item }}
   with_items: "{{ mounted_dirs.stdout_lines }}"
   register: umount_dir
+  when: mounted_dirs
   retries: 4
   until: umount_dir.rc == 0
   delay: 5