fix(plugin): fix error retrieving node by node id

[jnels124]

Pull Request template

Please, go through these steps before you submit a PR.

Why is this PR required? What issue does it fix?:
This pr is a follow up to pr #451 that pr had errors that were corrected but the changes were only in a rebase branch and not the PR branch. These are the changes that were intended to be merged for #451.

What this PR does?:
Fixes issues with retrieving nodes with custom node id
Does this PR require any upgrade changes?:
no
If the changes in this PR are manually verified, list down the scenarios covered::

1. Labeled all nodes via kubectl label node openebs.io/nodeid=value-1
2. Created persistent volumes
3. Ensured that the ZFSNode resources were created correctly.
4. Performed manual upgrade of the cluster
5. Attached the label with distinct value to each of the new nodes
6. Started test application to ensure that the volumes were mounted and accessible

Any additional information for your reviewer? :
Mention if this PR is part of any design or a continuation of previous PRs

Checklist:

• Fixes #
• PR Title follows the convention of <type>(<scope>): <subject>
• Has the change log section been updated?
• Commit has unit tests
• Commit has integration tests
• (Optional) Are upgrade changes included in this PR? If not, mention the issue/PR to track:
• (Optional) If documentation changes are required, which issue on https://github.com/openebs/openebs-docs is used to track them:

PLEASE REMOVE BELOW INFORMATION BEFORE SUBMITTING

The PR title message must follow convention:
<type>(<scope>): <subject>.

Where:

• type is defining if release will be triggering after merging submitted changes, details in CONTRIBUTING.md.
  Most common types are:

  • feat - for new features, not a new feature for build script
  • fix - for bug fixes or improvements, not a fix for build script
  • chore - changes not related to production code
  • docs - changes related to documentation
  • style - formatting, missing semi colons, linting fix etc; no significant production code changes
  • test - adding missing tests, refactoring tests; no production code change
  • refactor - refactoring production code, eg. renaming a variable or function name, there should not be any significant production code changes

• scope is a single word that best describes where the changes fit.
  Most common scopes are like:

  • data engine (localpv, jiva, cstor)
  • feature (provisioning, backup, restore, exporter)
  • code component (api, webhook, cast, upgrade)
  • test (tests, bdd)
  • chores (version, build, log, travis)

• subject is a single line brief description of the changes made in the pull request.