Remove ping-check of configured DHCP address.

This was added in 5ce3e76f but
it trips over too many buggy clients that leave an interface configured
even in DHCPDISCOVER case.

src/rfc2131.c

@@ -1040,8 +1040,6 @@ size_t dhcp_reply(struct dhcp_context *context, char *iface_name, int int_index,
 		  else if (have_config(config, CONFIG_DECLINED) &&
 			   difftime(now, config->decline_time) < (float)DECLINE_BACKOFF)
 		    my_syslog(MS_DHCP | LOG_WARNING, _("not using configured address %s because it was previously declined"), addrs);
-		  else if ((!lease || lease->addr.s_addr != config->addr.s_addr) && !do_icmp_ping(now, config->addr, 0, loopback))
-		    my_syslog(MS_DHCP | LOG_WARNING, _("not using configured address %s because it is in use by another host"), addrs);
 		  else
 		    conf = config->addr;
 		}