[kde-sunset] Change dependency from virtual/ghostscript to app-text/ghostscript-gpl

hi,

First of all - thanks for still maintaining KDE-3.5.
It's great to have an opportunity to use it, especially after Akonadi
and Nepomuk had become obligatory in the PIM part of KDE-4.4 .

Anyway - some packages in kde-sunset (e.g. kghostview or kdeprint) has
virtual/ghostscript as dependency. As it doesn't exist in the main
tree anymore, I think it should be replaced with
app-text/ghostscript-gpl.

greetings,
Paweł