Fix courtyard clearance for inductor (chocke) footprints

Next fix for the courtyard problems. For these the same applies, the old script did calculate the clearance relative to silk instead of body dimensions.

script PR: https://github.com/pointhi/kicad-footprint-generator/pull/127

I did again check all footprints using the footprint browser.

This revealed one error. L_Axial_L29.9mm_D14.0mm_P25.40mm_Horizontal_Vishay_IHA-105 is a bit strange. It is an axial inductor but the pitch is smaller then the length. This results in a totally wrong courtyard. I will look at this tomorrow. (It is 3 in the morning right now.)