dns: T5144: Explicitly override ddclient global options for reliability

• For option 'web', ddclient defaults to 'dyndns' which doesn't support ssl. This results ddclient process lockup till connection to checkip.dyndns.org:443 times out.
• For option 'use', ddclient defaults 'ip'. This results in confusing message "WARNING: '' is not a valid IPv4 or IPv6 address" in log.