Comment 25 for bug 1750656

Reviewed: https://review.openstack.org/547063
Committed: https://git.openstack.org/cgit/openstack/openstack-ansible-galera_server/commit/?id=ea7b8b253bee0c9bcee1a27a2fa4119bf1d70047
Submitter: Zuul
Branch: stable/ocata

commit ea7b8b253bee0c9bcee1a27a2fa4119bf1d70047
Author: git-harry <email address hidden>
Date: Tue Feb 20 20:57:00 2018 +0000

    Fix cache update after initial apt_repository fail

    If apt_repository fails to update the apt cache after updating the
    configuration, retries don't register there was a change and so no
    attempt is made to update the cache by the module on the second attempt.
    This failure can result in a failure to install packages.

    This change puts responsibility for updating the cache on the apt module
    task, this means updating the cache will get retried on failure and no
    longer fail silently.

    The changes made include:
    - the two apt_repository tasks have their update_cache parameter set to
      no so it is clear where any update happens and there is no unnecessary
      duplication of cache updates.
    - the use of retries is removed given the tasks no longer need to make
      use of the network.
    - the apt_repository task result variables have been given unique names
      to ensure that the cache is updated if only the galera repository is
      added.

    In addition, this cherry-pick separates out the cache update step from
    the install task so that the update is not performed for every item.

    Change-Id: I91b7929113f720bc3c55343c481096657376302f
    Partial-bug: 1750656
    (cherry picked from commit 7596eaa8898e774e4779417ac8c1fec38f634977)