Comment # 6 on bug 1163013 from Stefan Dirsch

[x] Or is it rather that the postuninstall of the old package runs after the
file has been created by the new version?

This one. :-) 

Yeah, let's close it as  INVALID. I could add more magic to %postun of kmp in
order to figure, that there is still some other KMP
around, but things are getting more and more complicated. And as said before
you're overwriting conflicts here ...