[PATCH] auth: support both old and new python-pam API

[Andrew Shadura]

# HG changeset patch
# User Andrew Shadura <andrew at shadura.me>
# Date 1456317153 -3600
#      Wed Feb 24 13:32:33 2016 +0100
# Node ID 9e0c363ed9eaf72fe0faf0da4a80065dc2faf8da
# Parent  05a85a6cecba5c8caeb7996590365d5d9bc523c9
auth: support both old and new python-pam API

python-pam 1.8.* provides a new API replacing the previously
available authenticate() function. The latest unreleased
version brings it back, but until it's available, use a
custom shim instead.

diff --git a/kallithea/lib/auth_modules/auth_pam.py b/kallithea/lib/auth_modules/auth_pam.py
--- a/kallithea/lib/auth_modules/auth_pam.py
+++ b/kallithea/lib/auth_modules/auth_pam.py
@@ -25,7 +25,13 @@ Original author and date, and relevant c
 
 import logging
 import time
-import pam
+
+try:
+    from pam import authenticate as pam_authenticate
+except ImportError:
+    from pam import pam
+    pam_authenticate = pam().authenticate
+
 import pwd
 import grp
 import re
@@ -92,7 +98,7 @@ class KallitheaAuthPlugin(auth_modules.K
             # Need lock here, as PAM authentication is not thread safe
             _pam_lock.acquire()
             try:
-                auth_result = pam.authenticate(username, password,
+                auth_result = pam_authenticate(username, password,
                                                settings["service"])
                 # cache result only if we properly authenticated
                 if auth_result: