Skip eviction in case when the Node is NotReady

[kron4eg]

What this PR does / why we need it:
When the Node is in NotReady condition, it's useless to try to drain it, causes endless loop of drain retrying of half-dead Node.

Which issue(s) this PR fixes:
Fixes #1586

What type of PR is this?
/kind bug
Special notes for your reviewer:

Does this PR introduce a user-facing change? Then add your Release Note here:

Skip eviction in case when the Node is NotReady

Documentation:

NONE

[kubermatic-bot]

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[kubermatic-bot]

@kron4eg: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-machine-controller-test	db2723b	link	true	/test pull-machine-controller-test

Full PR test history

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