Log Message:
kdeartwork4: fix builds with xscreensaver>=6.03

xscreensaver 6.x changed the name of a pre-existing screensaver
("rd-bomb" became "rdbomb"), and also webcollage is now built by
default when it was disabled before, which influences packaging here.
This package simply doesn't recognize "rdbomb" at the moment. If
someone really wants to include it, they'd need to patch several files
to handle the name change. This commit is concerned simply with getting
this package to build again.