Revert "dnsmasq: use "hostsdir" instead of "addn-hosts""

This reverts commit a03035d
as it has several issues:
-Host file is located in a directory which is not unique per dnsmasq instance
-odhcpd writes host info into the same directory but still sends a SIGHUP to dnsmasq

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>

package/network/services/dnsmasq/files/dnsmasq.init

@@ -938,7 +938,7 @@ dnsmasq_start()
 
 	xappend "--dhcp-broadcast=tag:needs-broadcast"
 
-	xappend "--hostsdir=$(dirname $HOSTFILE)"
+	xappend "--addn-hosts=$(dirname $HOSTFILE)"
 
 	config_get dnsmasqconfdir "$cfg" confdir "/tmp/dnsmasq.d"
 	[ ! -d "$dnsmasqconfdir" ] && mkdir -p $dnsmasqconfdir