Fix typo
Add EnergyIPMIVariable to use variables other than watts for mesurement.
Handy if you want to test the IMPI energy plugin but your ipmi doesn't
work with power.

EnergyIPMIVariable=Temp

Is the only thing accepted currently
IMPI - Move how defaults get defined
IPMI - If first variable fails look for the next one.
IPMI - get frequencies correct (hopefully)