Updates scsi rescan to use the LUN number in rescan command

[delldubey]

Description

This PR:

• This updates the rescan logic in findHCTLsForFCHBA function to use LUN number instead of '-', which scans for all the luns on a host.
• The LUN number is primarily part of NodeStageRequest.
• This saves us the issue of having a ghost/invalid sd* disk post NodeUnstage and there is a rescan for new devices at the same time.

GitHub Issues

List the GitHub issues impacted by this PR:

GitHub Issue #
dell/csm#1379

Checklist:

• I have performed a self-review of my own code to ensure there are no formatting, vetting, linting, or security issues
• I have verified that new and existing unit tests pass locally with my changes
• I have not allowed coverage numbers to degenerate
• I have maintained at least 90% code coverage
• I have commented on my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• Backward compatibility is not broken

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Please also list any relevant details for your test configuration

• Unit test
• Cluster test

[donatwork]

We can definitely do some regression testing with PowerStore.