dns/renewck: Fix duplicate "-d" short cmdline option

This patch fixes Duplicate specification "domain|d:s" for option "d" error.
The fix was provided by renewck author: Sergey Poznyakoff <gray@gnu.org.ua>
Quoting original email text from Sergey:

Thanks for reporting that. What happens is that the code defined short
option -d equivalent to two different long options: --debug (line 421)
and --domain (line 440). The warning you get just draws attention
to the fact (apparently it is reported by newer versions of
Getopt::Long). Please find attached a patch that fixes it.

PR: 275185