Comment 2 for bug 1841073

Reviewed: https://review.opendev.org/678047
Committed: https://git.openstack.org/cgit/openstack/kolla-ansible/commit/?id=331d373b996d9e7b7f9e6d9a1fa48821ddf1d62b
Submitter: Zuul
Branch: master

commit 331d373b996d9e7b7f9e6d9a1fa48821ddf1d62b
Author: Mark Goddard <email address hidden>
Date: Thu Aug 22 16:30:56 2019 +0100

    Don't assume etcd group exists in baremetal role

    The baremetal role does not currently assume too much about the
    inventory, and in kayobe the seed is deployed using a very minimal
    inventory.

    Icf3f01516185afb7b9f642407b06a0204c36ecbe added a reference to the etcd
    group in the baremetal role, which causes kayobe seed deployment to fail
    with the following error:

        AnsibleUndefinedVariable: 'dict object' has no attribute 'etcd'

    This change defaults the group lookup to an empty list.

    Change-Id: Ib3252143a97652c5cf70b56cbfd7c7ce69f93a55
    Closes-Bug: #1841073