pylint: Drop no longer used __home
    
    `__home` has been added in 8ca44bcbfa2aec0c7c84205dc08c81f711a22c5d,
    later `tests.util` was refactored in
    fd43b39145382b96cd2e0d0da3d5dcbe0d3a4a2a, but `__home` wasn't cleaned
    up.
    
    Fixes: https://pagure.io/freeipa/issue/9117
    Signed-off-by: Stanislav Levin <slev@altlinux.org>
    Reviewed-By: Rob Crittenden <rcritten@redhat.com>