ddns-scripts: Update to version 2.1.0-3

- removed special handling for dynamic_dns_helper.sh and url_escape.sed in Makefile/postinst
- minor fixes in logging
- allow retry_count of "0" to run infinite retrys on error
	-- https://dev.openwrt.org/ticket/18382
- changed naming of .dat and .err file to have one per section, not one per process
- defer hotplug helper from 25-ddns to 95-ddns (according initscript START=95)
	-- https://github.com/openwrt/packages/issues/568 (#568)
- fix commandline for busybox wget
	-- https://dev.openwrt.org/ticket/18411
	-- https://dev.openwrt.org/ticket/18437
	-- https://github.com/openwrt/packages/issues/605 (#605)
- remove checking answer from ddns provider because there are to many different.
	Some providers do not follow API from dyndns.com

Signed-off-by: Christian Schoenebeck <christian.schoenebeck@gmail.com>