Relays that are not directory authorities shouldn't load the approved-routers file
dirserv_load_fingerprint_file() is called from do_hup() and from
In do_hup() it's called if
authdir_mode_handles_descs(options, -1) != 0
In init_keys() it's called if
authdir_mode(options) != 0
This is inconsistent and at least one of them is wrong. I'm not quite sure exaclty who needs the fingerprints.