Use the lo feature of bisect.
Use the lo feature of bisect.

This ensures that we still skip the dot and dotdot records,
but we don't have a weird index + 2 return value.

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

clalancette/pycdlib,clalancette/pyiso