Add vexxhost connection to zuul-launcher

Thiss adds vexxhost as a second openstack cloud connection to the
zuul launcher.  This will help us benchmark image times for "raw"
images.

Change-Id: Ifdab5abb9915f384482eda844194f77e8d1b80ca

inventory/service/group_vars/zuul.yaml

@@ -50,6 +50,10 @@ zuul_connections:
     driver: 'openstack'
     cloud: 'raxflex'
 
+  - name: 'vexxhost'
+    driver: 'openstack'
+    cloud: 'vexxhost'
+
 openstacksdk_config_dir: /etc/openstack
 openstacksdk_config_owner: root
 openstacksdk_config_group: "{{ zuul_group }}"