portage_* dirs are treated as files

[gyver]

Once converted to directories the portage_* files aren't detected as directories by the os_gentoo module as true and false are converted to "true" and "false" both true for Puppet.

For example, using « if $use_is_file == "true" » instead of « if $use_is_file » works.

I believe it should be fixed in Puppet/Facter, but this one works.