Stop using legacy joliet=True in most places.
Stop using legacy joliet=True in most places.

Just leave one test to make sure it still works, but
otherwise switch to using joliet=3 as recommended in
the documentation.

Signed-off-by: Chris Lalancette <281cd07d7578d97c83271fbbf2faddb83ab3791c@gmail.com>

clalancette/pyiso,clalancette/pycdlib