nova: fix usage of scheduler_driver config option

The scheduler_driver option has been moved and deprecated. This
change uses the new group and name for the option.

Change-Id: I27aeff5911510c9f47191acaa0c0b5b71f977cd7
diff --git a/lib/nova b/lib/nova
index 9c3ba33..b7a0369 100644
--- a/lib/nova
+++ b/lib/nova
@@ -453,7 +453,7 @@
     fi
     iniset $NOVA_CONF wsgi api_paste_config "$NOVA_API_PASTE_INI"
     iniset $NOVA_CONF DEFAULT rootwrap_config "$NOVA_CONF_DIR/rootwrap.conf"
-    iniset $NOVA_CONF DEFAULT scheduler_driver "$SCHEDULER"
+    iniset $NOVA_CONF scheduler driver "$SCHEDULER"
     iniset $NOVA_CONF filter_scheduler enabled_filters "$FILTERS"
     iniset $NOVA_CONF DEFAULT default_floating_pool "$PUBLIC_NETWORK_NAME"
     if [[ $SERVICE_IP_VERSION == 6 ]]; then