inn-1.7-2 included a file, /usr/doc/inn-1.7/Install.txt that, its name notwithstanding, included crucial information about configuring the system. The 2.x analog, INSTALL, was not included in inn-2.2.1-1. (As an example, it took me a week of off-hours debugging before I discovered that the hosts.nntp configuration file had been replaced by incoming.conf.) This file should be included in future RPMs of INN.
Fixed in 2.2.2-2, which will be in the next rawhide release.