Add a functional vault job

Since we added a vault driver, we should add a functional job
so updates to castellan won't break the vault integration.

Change-Id: I4c15359618f907a9927ff6a4a730c10f429c0ec8

.zuul.yaml

@@ -1,3 +1,13 @@
+- job:
+    name: castellan-functional-vault
+    parent: openstack-tox-py27
+    description: |
+      Run tox functional-vault target
+    required-projects:
+      - name: openstack/castellan
+    vars:
+      tox_envlist: functional-vault
+
 - job:
     name: castellan-functional-devstack
     parent: devstack
@@ -40,7 +50,9 @@
     name: openstack/castellan
     check:
       jobs:
+        - castellan-functional-vault
         - castellan-functional-devstack
     gate:
       jobs:
+        - castellan-functional-vault
         - castellan-functional-devstack

test-requirements.txt

@@ -14,3 +14,4 @@ testscenarios>=0.4 # Apache-2.0/BSD
 testtools>=1.4.0 # MIT
 bandit>=1.1.0 # Apache-2.0
 reno>=2.5.0 # Apache-2.0
+pifpaf>=0.10.0 # Apache-2.0