Remove kDebug()-type methods from KSharedDataCache::Private::mapSharedMemory()

This change should make me more popular, as it prevents crashes from using kDebug before
a global component has been set. And it's probably for the best -- this code is called
very early in a kdelibs-user's startup it seems, before all the debug areas and such are
ready for use anyways.

In case there really are problems, we just fallback to Qt debugging facilities here.