OTP: fix data type to avoid endianness issue
    
    When 389-ds process an OTP authentication, the ipa-pwd-extop
    plugin reads a buffer to extract the authentication type.
    The type is stored in an int but the data is a ber_tag_t.
    
    On big endian machines the type cast does not cause any issue
    but on s390x the buffer that should return 128 is seen as 0.
    
    As a consequence, the plugin considers that the method is not
    LDAP_AUTH_SIMPLE and exits early, without processing the OTP.
    
    The fix is simple and consists in using the right type
    (ber_tag_t is an unsigned long).
    
    Fixes: https://pagure.io/freeipa/issue/9402
    
    Signed-off-by: Florence Blanc-Renaud <flo@redhat.com>
    Reviewed-By: Rob Crittenden <rcritten@redhat.com>