client: Fix CRL updating.

CRL object comparison does not check the list of revoked certificates.
Instead, compare signatures as they are supposed to be all-inclusive.

caucase/client.py

@@ -109,7 +109,7 @@ def updateCRLFile(url, crl_path, ca_list):
     ca_url=url,
   ).getCertificateRevocationList()
   latest_crl = utils.load_crl(latest_crl_pem, ca_list)
-  if latest_crl != my_crl:
+  if my_crl is None or latest_crl.signature != my_crl.signature:
     with open(crl_path, 'w') as crl_file:
       crl_file.write(latest_crl_pem)
     return True