unquote user/pass from nginx

nginx-mail-mapper did the same, which should be enough to make password with %
work, note however that nginx escapes only " " and "%" in this case
(function ngx_escape_uri)

authserv/app_nginx.py

 import socket
 import threading
+import urllib
 from flask import Flask, request, abort, make_response
 from authserv.app_common import do_auth
 
@@ -21,8 +22,8 @@ def _shard_to_ip(shard):
 @app.route('/', methods=('GET',))
 def do_nginx_http_auth():
     service = app.config.get('NGINX_AUTH_SERVICE', 'mail')
-    username = request.environ.get('HTTP_AUTH_USER')
-    password = request.environ.get('HTTP_AUTH_PASS')
+    username = urllib.unquote(request.environ.get('HTTP_AUTH_USER'))
+    password = urllib.unquote(request.environ.get('HTTP_AUTH_PASS'))
     source_ip = request.environ.get('HTTP_CLIENT_IP')
     protocol = request.environ.get('HTTP_AUTH_PROTOCOL')
     try: