Task 'Check if /etc/kubernetes/admin.conf file exists' fails when kubernetes_master.count = 0

[to-bar]

Repro steps:

1. In data.yml:

    kubernetes_master:
      count: 0
      machine: kubernetes-master-machine

2. Run epicli apply:

16:51:47 INFO cli.engine.ansible.AnsibleCommand - TASK [preflight_facts : Check if /etc/kubernetes/admin.conf file exists] *******************************************************************
16:51:47 INFO cli.engine.ansible.AnsibleCommand - fatal: [ec2-3-93-15-67.compute-1.amazonaws.com]: FAILED! => {"msg": "The conditional check 'inventory_hostname in groups.kubernetes_master' failed. The error was: error while evaluating conditional (inventory_hostname in groups.kubernetes_master): Unable to look up a name or access an attribute in template string ({% if inventory_hostname in groups.kubernetes_master %} True {% else %} False {% endif %}).\nMake sure your variable name does not contain invalid characters like '-': argument of type 'AnsibleUndefined' is not iterable\n\nThe error appears to be in '/workspaces/epiphany/core/src/epicli/clusters/build/small-test-ubu/ansible/roles/preflight_facts/tasks/kubernetes.yml': line 4, column 7, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n  block:\n    - name: Check if /etc/kubernetes/admin.conf file exists\n      ^ here\n"}
16:51:47 INFO cli.engine.ansible.AnsibleCommand - fatal: [ec2-174-129-166-186.compute-1.amazonaws.com]: FAILED! => {"msg": "The conditional check 'inventory_hostname in groups.kubernetes_master' failed. The error was: error while evaluating conditional (inventory_hostname in groups.kubernetes_master): Unable to look up a name or access an attribute in template string ({% if inventory_hostname in groups.kubernetes_master %} True {% else %} False {% endif %}).\nMake sure your variable name does not contain invalid characters like '-': argument of type 'AnsibleUndefined' is not iterable\n\nThe error appears to be in '/workspaces/epiphany/core/src/epicli/clusters/build/small-test-ubu/ansible/roles/preflight_facts/tasks/kubernetes.yml': line 4, column 7, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n  block:\n    - name: Check if /etc/kubernetes/admin.conf file exists\n      ^ here\n"}

[sk4zuzu]

Please note, that two more issues #1349 and #1350 have been discovered in addition to this regression problem.