[arch-general] Setting Computer Hostname via DHCP Server

[Taylor Hedberg]

dhcpcd should do this automatically. From dhcpcd(8):

    If the hostname is currently blank, (null) or localhost, or
    force_hostname is YES or TRUE or 1 then dhcpcd sets the hostname to
    the one supplied by the DHCP server.

It seems to work for me. If you're setting the hostname manually in
/etc/rc.conf, then you'll either need to remove that or run dhcpcd with
`-e force_hostname=TRUE` to override it.