ntome authored Oct 17, 2018 and Romain Bignon committed Feb 05, 2019

diff_percent was a misleading name because the ratio was expressed on 1,
not on 100, thus it wasn't a percentage.

For reference to suckers: a percentage is a ratio multiplied by 100.
We create a temporary alias so apps using the old field have compatibility.
"diff_percent" will soon be removed.