yet more strings in gdm2 were not marked for translation

[George <jirka 5z com>]

I found two more strings that weren't marked for translation in the graphical
greeter part of gdm2, so I marked them and they will be now translatable.
Sorry for not noticing this earlier.

George

-- 
George <jirka@5z.com>
   I can live with doubt and uncertainty and not knowing. I think it is much
   more interesting to live not knowing than to have answers that might be
   wrong.
                       -- Richard P. Feynman