Rendering SLS missing pillar key flakies

[TeddyAndrieux]

Component:

'salt'

What happened:

Time to time we got flaky error during upgrade, downgrade.

This is due to Endpoint not having any Ip, ports, ...

{
    "apiVersion": "v1",
    "kind": "Endpoints",
    "metadata": {
        "creationTimestamp": "2020-04-17T09:25:32Z",
        "labels": {
            "app": "repositories",
            "app.kubernetes.io/managed-by": "salt",
            "app.kubernetes.io/name": "repositories",
            "app.kubernetes.io/part-of": "metalk8s",
            "heritage": "metalk8s",
            "metalk8s.scality.com/version": "2.4.2"
        },
        "name": "repositories",
        "namespace": "kube-system",
        "resourceVersion": "898628",
        "selfLink": "/api/v1/namespaces/kube-system/endpoints/repositories",
        "uid": "c8181dad-e58a-4772-9e40-5e86a23ab165"
    }
}

What was expected:

No more flaky

Steps to reproduce

Flaky

Resolution proposal (optional):

Some try for a fix was already done 8feca89 but refresh_pillar is not synchronous instead of using refresh_pillar the check_pillar_keys function should import salt and use directly salt.pillar.get_pillar function.

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Note: A fresh pillar (with all ext_pillar) is gathered by salt-minion each and every time a salt state is executed