Run Shellcheck on instance reload command

[jmckulk]

Shellcheck was being run on the reload command for pgBackRest. During the auto-grow work, we noticed that the reload command for the instance was not being checked. Since we had to update the auto-grow bash logic to pass Shellcheck for pgBackRest, it seemed appropriate to enable the checks for the instance as well.

Checklist:

• Have you added an explanation of what your changes do and why you'd like them to be included?
• Have you updated or added documentation for the change, as applicable?
• Have you tested your changes on all related environments with successful results, as applicable?
  • Have you added automated tests?

Type of Changes:

• New feature
• Bug fix
• Documentation
• Testing enhancement
• Other

What is the current behavior (link to any open issues here)?

What is the new behavior (if this is a feature change)?

• Breaking change (fix or feature that would cause existing functionality to change)

Other Information:

[tjmoore4]

Looks good, I think we should just add a comment about the script updates.