Update operatingsystem.rb

Use additional confines instead of checks in setcode to detect the distribution ID

lib/facter/operatingsystem.rb

@@ -2,13 +2,10 @@ Facter.add(:operatingsystem) do
    # Sabayon Linux is a variant of Gentoo so this resolution needs to come
    # before the Gentoo resolution.
    has_weight(100)
-   confine :kernel => :linux
+   confine kernel: :linux, lsbdistid: :sabayon
 
    setcode do
-     distid = Facter.value(:lsbdistid)
-     if distid == "Sabayon"
-       'Sabayon'
-     end
+     'Sabayon'
    end
  end