Some map models are not properly lit

[illwieckz]

Some map models are not properly lit:

That rings a bell but I don't remember what.

I was playing on Der Bunker (still 0.54.0 based if I'm right) while using 0.54.1 engine.

[illwieckz]

Regression introduced by me in 56d0d83.

[illwieckz]

The way it looks makes me think that the grid light is not used when there is no lightmap, even if there is a grid light, so the model ends fullbright.