Since rev 1.543 of dhclient it sends the 'host-name' by default.

Since rev 1.543 of dhclient it sends the 'host-name' by default.

- remove the leftover _hn variable from dhcp_request()
- remove the "$_name" parameter when using dhcp_request() in v4_config()
- change comments of v{4,6}_config() to reflect the purpose of _name

OK krw tb