cubicweb #2357044 broken db-api request [validation pending]

a typo make request crash if vreg has no translation set (eg pyro client)

prioritynormal
typebug
done in3.15.1
load0.100
load left0.000
closed by#3dcb117fb3b0 [db-api] fix typo leading to crash on client connection (config has no translations). Closes #2357044