Fix handling of remote targets for Ohai

[thheinen]

Description

• Fix platform type :target to specify an os_version attribute.
  This allows including a related plugin inside a cookbook's ohai segment as opposed to installation in the system (Crash due to Chef trying to access a nil value)
• Add platform type :api to enable REST APIs as opposed to agent-less OS (e.g. Switches)
• Fix a return value of Object type as opposed to all other branches returning String for this
• Fix missing ? on nonruby_target? check

Related Issue

Bug fixes, somewhat Hackathon related... ;-)

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)
• Chore (non-breaking change that does not add functionality or fix an issue)

Checklist:

• I have read the CONTRIBUTING document.
• I have run the pre-merge tests locally and they pass.
• All new and existing tests passed.
• All commits have been signed-off for the Developer Certificate of Origin.

[tas50]

Thanks @tecracer-theinen