update baremetal option names

update power_manager and instance_type_extra_specs config opts
to match the new values in nova, introduced by
https://review.openstack.org/#/c/17994/

Change-Id: Ic624362df17c217406e142ef4c2e65a4c0c2765d
diff --git a/stack.sh b/stack.sh
index 1ee669d..53b892f 100755
--- a/stack.sh
+++ b/stack.sh
@@ -1124,8 +1124,8 @@
         add_nova_opt "firewall_driver=$LIBVIRT_FIREWALL_DRIVER"
         add_nova_opt "baremetal_driver=$BM_DRIVER"
         add_nova_opt "baremetal_tftp_root=/tftpboot"
-        add_nova_opt "instance_type_extra_specs=cpu_arch:$BM_CPU_ARCH"
-        add_nova_opt "power_manager=$BM_POWER_MANAGER"
+        add_nova_opt "baremetal_instance_type_extra_specs=cpu_arch:$BM_CPU_ARCH"
+        add_nova_opt "baremetal_power_manager=$BM_POWER_MANAGER"
         add_nova_opt "scheduler_host_manager=nova.scheduler.baremetal_host_manager.BaremetalHostManager"
         add_nova_opt "scheduler_default_filters=AllHostsFilter"