Added this in before it gets forgotten, thanks.

@razic I'm going to take a look what it would require to port these facts over to your refactor branch and integrate them there.  I think the idea of having these things come from facts is pretty powerful and compelling, and wouldn't take massive changes to your branch to integrate.  Unless you strongly oppose the idea of having them as facts, that is!  I just think you've done 90% of the work so integrating these would finish up the last bits.  (Unless I misunderstand your refactoring won't use /sbin/ip instead of /sbin/ifconfig, or different regexps for those cases etc, which these facts will give us).