Reset descending/ascending order when changing sort column
Reset descending/ascending order when changing sort column

This changes the behaviour back to it was before the dirlist
abstraction, which is the behaviour I prefer.

guns/ncdu,guns/ncdu,guns/ncdu,gitkaste/ncdu,rofl0r/ncdu,rofl0r/ncdu,ppetr/ncdu,FauxFaux/ncdu,ppetr/ncdu,sunny256/ncdu,ppetr/ncdu,sunny256/ncdu,FauxFaux/ncdu,gitkaste/ncdu,piyo/ncdu