Update GoDoc field name references to use the JSON field name

[everettraven]

As outlined in the Use JSON Field Names in GoDoc subsection of the OpenShift API Conventions, field names referenced in the GoDoc should use the JSON field names.

The updates required as of writing this are:

• Version → version, ref
• Channel → channel, ref
• Preflight → preflight, ref
• ServiceAccount → serviceAccount, ref
• InstalledBundle → installedBundle, ref
• CRDUpgradeSafety → crdUpgradeSafety, ref
• Disabled → disabled, ref