Fixed crashing bug, final check before submit

[Cyrille Berger]

> It sounds good; I haven't tried applying to 1.6 yet -- I'll give it a try
> tonight.
I don't like the idea to give the ability to convert the colorspace of a layer 
for two reasons:
1) that would give two ways of converting layers
2) we have two very similar dialog, image properties and layer properties, 
and, one of them will convert colorspaces, while the other one won't, I think 
it will be even more confusing for users.


-- 
Cyrille Berger