Check for variations of $is_pe

[zachfi]

On recent versions of facter, we need to check for a boolean value, but
to support older versions of Facter, we need to check for a string.

[elyscape]

Potentially superior alternative:

if $::is_pe == true || str2bool($::is_pe) == true:

This would also solve the issue of linting frowning on the quoted 'true'.

[zachfi]

I'd argue that lint is complaining about an invalid check, since all facts in older versions of facter are strings and thus to do a comparisons you will sometimes have the word 'true' or 'false' in a string. I can change if its preferred. I don't really care.

[elyscape]

That's certainly fair. @acidprime, your thoughts?

[acidprime]

merging for right now as this effects anyone using the future parser