Fix typo in ironic configure function

IRONIC_CONF should be replaced by IRONIC_CONF_FILE

Change-Id: Ie43e376f42f14c46d21df7dbb19db923521f438b
diff --git a/lib/ironic b/lib/ironic
index 4e5edc9..b346de1 100644
--- a/lib/ironic
+++ b/lib/ironic
@@ -124,7 +124,7 @@
     cp $IRONIC_DIR/etc/ironic/rootwrap.conf $IRONIC_ROOTWRAP_CONF
     cp -r $IRONIC_DIR/etc/ironic/rootwrap.d $IRONIC_CONF_DIR
 
-    iniset $IRONIC_CONF DEFAULT rootwrap_config $IRONIC_ROOTWRAP_CONF
+    iniset $IRONIC_CONF_FILE DEFAULT rootwrap_config $IRONIC_ROOTWRAP_CONF
 }
 
 # create_ironic_cache_dir() - Part of the init_ironic() process