Remove py-libzfs as iocage submodule
We have py-libzfs as a submodule in iocage right now. We should remove that and use pkg for installing it.
We risk breaking the installation of iocage
Iocage should be built from sources, and if it succeeds, this ticket can be marked as resolved. Secondly, it would be better if py-libzfs isn't installed in the testing system and iocage installs it itself.