cubicweb-geocoding #3001759 drop pre-cubicweb 3.9 bw compat code [validation pending]

This bw compat is scheduled to disappear from cw itself at around 3.18.

prioritynormal
typeenhancement
done in0.2.0
load0.100
load left0.000
closed by#1e5c17ff7bcc [views] drop pre-cw 3.9 era bw-compat (closes #3001759)
patch[views] drop pre-cw 3.9 era bw-compat (closes #3001759) [applied]