Overhaul dhcpcd for chrome os use

dhcpcd-hooks/29-lookup-hostname

-# Lookup the hostname in DNS if not set
-
-lookup_hostname()
-{
-        [ -z "$new_ip_address" ] && return 1
-        local h=
-        # Silly ISC programs love to send error text to stdout
-        if type dig >/dev/null 2>&1; then
-                h=$(dig +short -x $new_ip_address)
-                if [ $? = 0 ]; then
-                        echo "$h" | sed 's/\.$//'
-                        return 0
-                fi
-        elif type host >/dev/null 2>&1; then
-                h=$(host $new_ip_address)
-                if [ $? = 0 ]; then 
-                        echo "$h" \
-                        | sed 's/.* domain name pointer \(.*\)./\1/'
-                        return 0
-                fi
-        fi
-        return 1
-}
-
-set_hostname()
-{
-        if [ -z "$new_host_name" -a -z "$new_fqdn_name" ]; then
-                export new_host_name="$(lookup_hostname)"
-        fi
-}
-
-case "$reason" in
-BOUND|INFORM|REBIND|REBOOT|RENEW|TIMEOUT|STATIC)        set_hostname;;
-esac