refactor(rebuild): tidy up helm variables for rebuild

[tiagolobocastro]

Tidy up all rebuild related vars in rebuild and partial dicts.

Description

Motivation and Context

Regression

How Has This Been Tested?

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added unit tests to cover my changes.

[tiagolobocastro]

bors merge

[bors-openebs-mayastor]

Build succeeded:

• continuous-integration/jenkins/branch