extensions: preparatory refactoring Small refactoring: - use 'try..except' rather than 'if-then', which removes the need for a separate 'path' variable and is more 'pythonic'. - promote log from 'debug' to 'info' and execute it immediately after loading before anything else. - clarify comments related to INDEX_EXTENSIONS

[tox]
minversion = 1.8
envlist = py27-pytest

[testenv]
setenv =
    PYTHONHASHSEED = 0
deps =
    -r{toxinidir}/dev_requirements.txt
    python-ldap
    python-pam
commands =
    pytest: py.test {posargs}