dhclient's mysterious option -D (missing)

Hello,

today I tried to debug dhclient, and found one little problem ;)
Although -D option is documented in man page (dhclient.8) and in
dhclient.c (usage()), dhclient doesn't recognize it.
The core functionality of it was removed in dhclient.c revision 1.12.
The option was removed in dhclient.c revision 1.20.
The variable save_scripts was removed in dhclient.c revision 1.23.

As long as it seems no one noticed this for a while, it would be best
to remove it from usage and man page ;) or reimplement (although,
original dhclient from isc-dhcp doesn't implement this).

I filled a PR bin/60642 with patch for removal ;)

Regards,
Paulius