tests/readlink.py

tests: fix deprecation warning about regex flags not at beginning of expr

This may only show up when running the tests under python3.6+. Currently the
only test that does this is test-patchbomb-tls.t, and it only uses (?i), so
that's all that's handled at the moment.

Differential Revision: https://phab.mercurial-scm.org/D7552

#!/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)