anaconda bug #466775 was affected by a change in the recent NetworkManager build that appeared in rawhide. The Hostname property is no longer available via D-Bus, which is how we were getting the hostname to display in the installer. The latest nightly build has broken network installations for everyone because of this problem. If this is a permanent change to NetworkManager, it should wait for F-11. We are in a development freeze for F-10 at this point.
clumens and I went over this yesterday and he should have fixed it... the fallback code to gethostname(2) is actually correct; just the bits to ask NM for the hostname should be removed. Having the hostname as part of the IP4 config doesn't make sense since it's machine global, and gethostname(2) would always have returned the correct result if the hostname was changed anyway...