Do not sign logout requests if not specified to do so

Signed-off-by: Ivan Kanakarakis <ivan.kanak@gmail.com>

Author: c00kiemon5ter

src/saml2/client.py

@@ -257,10 +257,6 @@ def do_logout(self, name_id, entity_ids, reason, expire, sign=None,
                     destination, entity_id, name_id=name_id, reason=reason,
                     expire=expire, session_indexes=session_indexes)
 
-                # to_sign = []
-                if binding.startswith("http://"):
-                    sign = True
-
                 if sign is None:
                     sign = self.logout_requests_signed