Handle binascii.Error from base64.b64decode()
    
    In Python 3, the base64.b64decode function raises binascii.Error (a ValueError
    subclass) when it finds incorrect padding. In Python 2 it raises TypeError.
    
    Callers should usually handle ValueError; unless they are specifically
    concerned with handling base64 padding issues).
    
    In some cases, callers should handle ValueError:
    - ipalib.pkcs10 (get_friendlyname, load_certificate_request): callers should
      handle ValueError
    - ipalib.x509 (load_certificate*, get_*): callers should handle ValueError
    
    In other cases ValueError is handled:
    - ipalib.parameters
    - ipapython.ssh
    - ipalib.rpc (json_decode_binary - callers already expect ValueError)
    - ipaserver.install.ldapupdate
    
    Elsewhere no error handling is done, because values come from trusted
    sources, or are pre-validated:
    - vault plugin
    - ipaserver.install.cainstance
    - ipaserver.install.certs
    - ipaserver.install.ipa_otptoken_import
    
    Reviewed-By: Tomas Babej <tbabej@redhat.com>