Adapt InSpec to work with latest train OS updates

[chris-rock]

Description

@stevendanna introduced a couple of updates for our OS detection: inspec/train#126. This PR changes the way we get os information:

# old
@platform[:family] = 'centos'

# new 
@platform[:name] = 'centos'
@platform[:family] = 'redhat'

InSpec and Platform Version

latest

Possible Solutions

We should prefer to use dynamic methods like inspec.os.linux? or inpsec.os.debian? in our resource implementations. In addition we need to update the mock helper to reflect the changes: https://github.com/chef/inspec/blob/master/test/helper.rb#L40-L59

[chris-rock]

In addition, we need to ensure that Amazon Linux is supported, since this is now its own family.