Comment # 1 on bug 1189962 from Hannes Reinecke

This patch is conceptually similar to the 'dm-queuelength' path selector, and
could be superseded by that. So we could drop it, but need to be aware that we
need to keep compability with previous releases (which had this scheduler).
So easiest would be to keep it for the time being, and drop it when we switch
to the next major version (if and when that happens).