Ironic: Use HOST_IP instead of SERVICE_HOST

Ironic virtual machines boot on a different network and are expected
to fetch via tftp from the conductor and callback to the API.  We
need to ensure both endpoints are accessible, even when SERVICE_HOST
is 127.0.0.1 (eg, devstack-gate).

Change-Id: I96aee75b76ad11d83143736da00ea304db971c9c
diff --git a/lib/ironic b/lib/ironic
index e5dc117..0fc5664 100644
--- a/lib/ironic
+++ b/lib/ironic
@@ -158,8 +158,8 @@
     cp -r $IRONIC_DIR/etc/ironic/rootwrap.d $IRONIC_CONF_DIR
 
     iniset $IRONIC_CONF_FILE DEFAULT rootwrap_config $IRONIC_ROOTWRAP_CONF
-    iniset $IRONIC_CONF_FILE conductor api_url http://$SERVICE_HOST:6385
-    iniset $IRONIC_CONF_FILE pxe tftp_server $SERVICE_HOST
+    iniset $IRONIC_CONF_FILE conductor api_url http://$HOST_IP:6385
+    iniset $IRONIC_CONF_FILE pxe tftp_server $HOST_IP
     iniset $IRONIC_CONF_FILE pxe tftp_root $IRONIC_TFTPBOOT_DIR
     iniset $IRONIC_CONF_FILE pxe tftp_master_path $IRONIC_TFTPBOOT_DIR/master_images
 }