Adding back the 1st master node back into the cluster after it was removed

Issue

• Due to disk corruption, the 1st master node (as per in the inventory file) was forced to be removed from the cluster.

• While trying to add back a new master node, it may cause a failure either with the add-cns-storage.py or add-node.py playbooks. The failure occurs during the step Generate the node client config.

failed: [node3.example.com -> master1.example.com] (item=node3.example.com) => {
    "changed": true,
    "cmd": [
        "oc",
        "adm",
        "create-api-client-config",
        "--certificate-authority=/etc/origin/master/ca.crt",
        "--client-dir=/etc/origin/generated-configs/node-ip-xx-xx-xx-xx.compute.internal",
        "--groups=system:nodes",
        "--master=https://internal-openshift-master.example.com",
        "--signer-cert=/etc/origin/master/ca.crt",
        "--signer-key=/etc/origin/master/ca.key",
        "--signer-serial=/etc/origin/master/ca.serial.txt",
        "--user=system:node:ip-xx-xx-xx-xx.compute.internal"
    ],
    "delta": "0:00:00.158849",
    "end": "2020-04-17 17:27:29.789575",
    "failed": true,
    "item": "node3.example.com",
    "rc": 1,
    "start": "2020-04-17 17:27:29.630726",
    "warnings": []
}

STDERR:

error: --signer-serial, "/etc/origin/master/ca.serial.txt" must be a valid file
See 'oc adm create-api-client-config -h' for help and examples.