Switch things to using one variable for LE and BE.
Switch things to using one variable for LE and BE.

For all of the sizes, the little-endian and big-endian
versions we read out of the original ISO should agree.
Make sure that is the case, and then only store the
little-endian one and swab it as needed.

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

clalancette/pyiso,clalancette/pycdlib