Enable Barbican DevStack plugin

* Enforce presence of Barbican in DevStack configuration
* Add Barbican and python-barbicanclient to stx-devstack-metal job

Change-Id: I3df338785b2352ec9e9f7c1387f2fbb47bb7baca
Signed-off-by: Dean Troyer <dtroyer@gmail.com>

.zuul.yaml

@@ -27,6 +27,8 @@
     parent: stx-devstack-base
     timeout: 7800
     required-projects:
+      - openstack/barbican
+      - openstack/python-barbicanclient
       - openstack/stx-update
       - openstack/stx-fault
       - openstack/stx-nfv
@@ -52,6 +54,7 @@
         pmon: true
         rmon: true
       devstack_plugins:
+        barbican: https://git.openstack.org/openstack/barbican
         stx-fault: git://git.starlingx.io/stx-fault
         stx-metal: git://git.starlingx.io/stx-metal
         stx-nfv: git://git.starlingx.io/stx-nfv

devstack/settings

@@ -37,8 +37,13 @@ enable_service $STX_METAL_NAME
 # This must not use any variables to work properly in OpenStack's DevStack playbook
 define_plugin stx-metal
 # This works for Zuul jobs using OpenStack's DevStack roles
+plugin_requires stx-metal barbican
 plugin_requires stx-metal stx-fault
 
+if ! is_service_enabled barbican; then
+    die $LINENO "Barbican is required"
+fi
+
 if is_service_enabled mtce-components; then
     enable_service fsmon hbs hwmon mtce mtcalarm mtclog pmon
 fi