remove useless base64 decoding from WSGI middleware

src/python/sso/middleware.py

-import base64
 import cgi
 import logging
 import sso
@@ -96,7 +95,7 @@ class SSOMiddleware:
             if self.cookie_name in cookies:
                 ticket = cookies[self.cookie_name].value
                 try:
-                    tkt = self.verifier.verify(base64.b64decode(ticket))
+                    tkt = self.verifier.verify(ticket)
                     environ['sso.ok'] = True
                     environ['REMOTE_USER'] = tkt.user()
                     return self.next_app(environ, start_response)