Rudder

#3289 introduced a nice pass of UNIX support, but missed out a couple of important cases:

• We only ran detection of the CFEngine key and CFEngine user and user list on Windows, Android and Linux. That should also be run on all systems, using the UNIX default paths.
• We tried to use dmidecode to get a machine ID on all non-Windows, non-Android systems. That obviously doesn't work. I'm fixing this one by adding in support for known OSes, for now AIX.

On AIX, we will use "uname -f" as a machine ID. From http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.cmds/doc/aixcmds5/uname.htm, this provides:

-F Displays a system identification string comprised of hexadecimal characters. This identification string is the same for all partitions on a particular system.
-f Similar to the F flag, except that the partition number is also used in the calculation of this string. The resulting identification string is unique for each partition on a particular system.