bug#18196: 24.4.50; crash when setting face background in terminal frame

[martin rudalics]

> Oh, hello. I am in the process of relocating and won't see my laptop until 
Monday.
>
> I am sorry I cannot confirm the patch works on this occasion.

I meanwhile checked it in on trunk as revision#117679.  Please update
your trunk as soon as you can and tell me whether it fixes your bug.

Thanks, martin