Make devstack-tempest job voting

Since the zuul jobs have been converted to the new format (see commit de4a38e),
the devstack-tempest job is stable. In consequence, this makes this job voting.
Given that the "cloudkitty-devstack-install" job was the same as the
devstack-tempest job without the tempest run, it has been removed in order to
put less load on the gate.

Change-Id: I942f9069eedce033b0b087992f8b84c76149ff1a

.zuul.yaml

@@ -1,26 +1,3 @@
-- job:
-    name: cloudkitty-devstack-install
-    parent: devstack
-    description: |
-      Job testing cloudkitty installation on devstack
-    required-projects:
-      - name: openstack/cloudkitty
-      - name: openstack/python-cloudkittyclient
-    roles:
-      - zuul: openstack-infra/devstack
-    timeout: 5400
-    irrelevant-files:
-      - ^.*\.rst$
-      - ^doc/.*$
-      - ^releasenotes/.*$
-    vars:
-      devstack_plugins:
-        cloudkitty: https://git.openstack.org/openstack/cloudkitty
-      devstack_services:
-        ck-api: true
-        ck-proc: true
-        horizon: false
-
 - job:
     name: cloudkitty-tempest-full
     parent: devstack-tempest
@@ -64,10 +41,8 @@
       - release-notes-jobs-python3
     check:
       jobs:
-        - cloudkitty-tempest-full:
-            voting: false
-        - cloudkitty-devstack-install
+        - cloudkitty-tempest-full
     gate:
       queue: cloudkitty
       jobs:
-        - cloudkitty-devstack-install
+        - cloudkitty-tempest-full