The ipa-client-install script sets the "server" setting in /etc/ipa/default.conf, but doesn't set "host". The default.conf(5) man page notes that "server" is deprecated, and that the "host" value is used for constructing URL values on the client and server, so if the file's only going to provide one of the settings, it should be the other one (though, it looks pretty inexpensive to provide both, at least in the short-term).