Fix keystoneclient-devstack-functional job

The keystoneclient-devstack-functional job works fine when being run
against this repo, but fails when running against the keystone repo
because of conflicts within the tools/test-setup.sh script there.

Do our own definition of the job to make sure that we always run tox
against the correct repo. Also base the job on devstack-minimal to avoid
installing more serviced than needed.

Change-Id: Ie4c03de48a3b7f2fb3967a185486c6fb0d6e0a5f

.zuul.yaml

@@ -1,14 +1,19 @@
 - job:
     name: keystoneclient-devstack-functional
-    parent: devstack-tox-functional-consumer
+    parent: devstack-minimal
     timeout: 4200
     required-projects:
       - openstack/keystone
       - openstack/python-keystoneclient
+    run: playbooks/run-ds-tox.yaml
+    post-run: playbooks/tox-post.yaml
     vars:
-      tox_envlist: functional
       devstack_localrc:
         USE_PYTHON3: True
+      devstack_services:
+        key: true
+      tox_envlist: functional
+      zuul_work_dir: src/git.openstack.org/openstack/python-keystoneclient
 
 - project:
     templates:

playbooks/run-ds-tox.yaml

@@ -0,0 +1,5 @@
+- hosts: all
+  roles:
+    - run-devstack
+    - ensure-tox
+    - tox

playbooks/tox-post.yaml

@@ -0,0 +1,4 @@
+- hosts: all
+  roles:
+    - fetch-tox-output
+    - fetch-subunit-output