Adding postfix plugin for ohai-solo

I wrote a little plugin for ohai-solo to discover current postfix configuration.
I decided to make it work only in case of RPM/DEB installed packages, and to look only at very few, but important config options, which can tell why mail delivery might not be working or not.

I thought about adding a method to check the size of outgoing mail queue, however I remember that running mailq on a server that has a huge queue, will take ages, before it produces the result you want, therefore I decided not to include that, to avoid affecting waldo or the target server.

Marcin
Hey Caleb,
this is all good but what the whole IF statement here is for, is not that ! I know already that the ohai plugin will not return anything if the given thing is not installed.
The reason for such logic here is:
If postfix instaleld from packages: do the checks, otherwise - see if there is a postfix binary, and display INFo message that we do not suport "hand compiled installations"