Fedora is migrating away from:
 /etc/sysconfig/network (the HOSTNAME=... setting)
 /etc/sysconfig/keyboard
 /etc/sysconfig/i18n
to:
 /etc/hostname
 /etc/vconsole.conf
 /etc/locale.conf

See the tracker bug 881785 for details.

We found:
In libguestfs-1.19.64/src/inspect-fs-unix.c:check_hostname_unix():
- the code correctly handles /etc/hostname, but you may want to update the comment about Red Hat-derived distros.

libguestfs-1.19.64/tests/guests/guest-aux/make-fedora-img.pl:
libguestfs-1.19.64/sysprep/sysprep_operation_hostname.ml:
libguestfs-1.19.64/sysprep/sysprep_operation_net_hostname.ml:
- write HOSTNAME to /etc/sysconfig/network

Please update the package for the new config files.