energy_model: Don't error if energy model data is dodgy
energy_model: Don't error if energy model data is dodgy

People have energy models with kinks in the data and still need to
use this module. Just print a warning instead of erroring out.

credp/lisa,arnoldlu/lisa,mdigiorgio/lisa,credp/lisa,credp/lisa,credp/lisa,bjackman/lisa,ARM-software/lisa,ARM-software/lisa,bjackman/lisa,ARM-software/lisa,arnoldlu/lisa,mdigiorgio/lisa,ARM-software/lisa