createiso: Create Joliet tree with xorriso

This structure is important for isoinfo -J, which is in turn called by
virt-install.

This can be tested by using a bootable ISO by modifying it with a dummy
additional file and preserving boot records:

    $ xorriso -indev netinst.iso -outdev test.iso -boot_image any replay -map setup.py setup.py -end
    ...
    $ isoinfo -J -i test.iso
    isoinfo: Unable to find Joliet SVD
    $ rm test.iso
    $ xorriso -indev netinst.iso -outdev test.iso -joliet on -boot_image any replay -map setup.py setup.py -end
    ...
    $ isoinfo -J -i test.iso
    $

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=2144105
Signed-off-by: Lubomír Sedlář <lsedlar@redhat.com>

pungi/createiso.py

@@ -125,6 +125,8 @@ def write_xorriso_commands(opts):
         emit(f, "-outdev %s" % os.path.join(opts.output_dir, opts.iso_name))
         emit(f, "-boot_image any replay")
         emit(f, "-volid %s" % opts.volid)
+        # isoinfo -J uses the Joliet tree, and it's used by virt-install
+        emit(f, "-joliet on")
 
         with open(opts.graft_points) as gp:
             for line in gp: