Use separate client for leader election

[RaunakShah]

What type of PR is this?
/kind bug

What this PR does / why we need it:
This PR uses a separate client for leader election. In case of throttling of API server due to snapshot controller, leader election routine will remain unaffected.

Which issue(s) this PR fixes:

Fixes #343

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

Use a separate API server client for leader election.

[k8s-ci-robot]

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[k8s-ci-robot]

Hi @RaunakShah. Thanks for your PR.

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[xing-yang]

/ok-to-test

[xing-yang]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: RaunakShah, xing-yang

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