code coverage for storagequota

[kavyashree-r]

What this PR does / why we need it:

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

Testing done: A PR must be marked "[WIP]", if no test result is provided. A WIP PR won't be reviewed, nor merged. The requester can determine a sufficient test, e.g. build for a cosmetic change, E2E test in a predeployed setup, etc. For new features, new tests should be done, in addition to regression tests. If jtest is used to trigger precheckin tests, paste the result after jtest completes and remove [WIP] in the PR subject. The review cycle will start, only after "[WIP]" is removed from the PR subject.

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Release note:

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: kavyashree-r Once this PR has been reviewed and has the lgtm label, please assign chethanv28 for approval. For more information see the Kubernetes Code Review Process.

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Needs approval from an approver in each of these files: - **[OWNERS](https://github.com/kubernetes-sigs/vsphere-csi-driver/blob/master/OWNERS)** Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[k8s-ci-robot]

@kavyashree-r: 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-vsphere-csi-driver-unit-test	ca172fbec4e7f6dabcd1ae01e238fb39431c1a3e	link	true	/test pull-vsphere-csi-driver-unit-test

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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