Fix order of reads dhcp-hostsfile and /etc/ethers.

Reading /etc/ethers assumes that dhcp-host cofig has already
been read, and that is the case for dhcp-host, but for unknown
reasons, the analogous congiguration is dhcp-hostfile was being
read after /etc/ethers.

Swap the order.

Thanks to Andreas Kuropka for spotting the problem.

src/dnsmasq.c

@@ -1777,9 +1777,9 @@ void clear_cache_and_reload(time_t now)
 #ifdef HAVE_DHCP
   if (daemon->dhcp || daemon->doing_dhcp6)
     {
+      reread_dhcp();
       if (option_bool(OPT_ETHERS))
 	dhcp_read_ethers();
-      reread_dhcp();
       dhcp_update_configs(daemon->dhcp_conf);
       lease_update_from_configs(); 
       lease_update_file(now);