tests/readlink.py

config: use the new '_unset' value for 'configbool'

This should let 'configbool' delegate all special processing of the default
config value to the main 'config' method.

The default value for bool (False) is still enforced in this method if no other
default were passed.

#!/usr/bin/env python

from __future__ import absolute_import, print_function

import errno
import os
import sys

for f in sys.argv[1:]:
    try:
        print(f, '->', os.readlink(f))
    except OSError as err:
        if err.errno != errno.EINVAL:
            raise
        print(f, '->', f, 'not a symlink')

sys.exit(0)