Use Fedora 23 for Barbican's Dogtag job

The setup in Fedora 21 is broken due to some package issues. On the
other hand, Fedora 21 will be EOL soon. So upgrading to Fedora 23 is the
best step in the long run.

Change-Id: I77fa548e4bc96682808d3721bc5528e091871b6a

jenkins/jobs/barbican.yaml

@@ -40,8 +40,8 @@
       - console-log
 
 - job:
-    name: gate-barbican-dogtag-devstack-dsvm-f21-oldstable
-    node: 'devstack-f21'
+    name: gate-barbican-dogtag-devstack-dsvm-f23-oldstable
+    node: 'fedora-23'
 
     wrappers:
       - build-timeout:
@@ -121,8 +121,8 @@
       - console-log
 
 - job:
-    name: gate-barbican-dogtag-devstack-dsvm-f21
-    node: 'devstack-f21'
+    name: gate-barbican-dogtag-devstack-dsvm-f23
+    node: 'fedora-23'
 
     wrappers:
       - build-timeout:

zuul/layout.yaml

@@ -1379,11 +1379,11 @@ jobs:
   - name: gate-barbican-devstack-dsvm-oldstable
     branch: ^stable/(juno|kilo)$
 
-  - name: gate-barbican-dogtag-devstack-dsvm-f21
+  - name: gate-barbican-dogtag-devstack-dsvm-f23
     voting: false
     branch: ^(?!stable/(?:juno|kilo)).*$
 
-  - name: gate-barbican-dogtag-devstack-dsvm-f21-oldstable
+  - name: gate-barbican-dogtag-devstack-dsvm-f23-oldstable
     voting: false
     branch: ^stable/(juno|kilo)$
 
@@ -3746,8 +3746,8 @@ projects:
       - gate-barbican-devstack-dsvm-oldstable
       - barbican-coverage
       - gate-barbican-tox-bandit
-      - gate-barbican-dogtag-devstack-dsvm-f21
-      - gate-barbican-dogtag-devstack-dsvm-f21-oldstable
+      - gate-barbican-dogtag-devstack-dsvm-f23
+      - gate-barbican-dogtag-devstack-dsvm-f23-oldstable
     gate:
       - gate-barbican-devstack-dsvm
       - gate-barbican-devstack-dsvm-oldstable