edit-node: Add isofs kernel module

Lately the isofs got extracted into a kmod, this now needs to be added
to the initramfs.
Additionally we need to reove isofs from the blacklisting to make it
available inside of the image - where dracut is generating the new
initramfs.

Change-Id: Ibc3d244c4594885a3a907f51a4ec580baad19b8c
Signed-off-by: Fabian Deutsch <fabiand@fedoraproject.org>