Comment 60 for bug 1750656

Reviewed: https://review.openstack.org/547471
Committed: https://git.openstack.org/cgit/openstack/openstack-ansible-rabbitmq_server/commit/?id=76fc65b4e7a158628aff8f3a95ec91a0ec3ce2f0
Submitter: Zuul
Branch: master

commit 76fc65b4e7a158628aff8f3a95ec91a0ec3ce2f0
Author: Jesse Pretorius <email address hidden>
Date: Fri Feb 23 14:53:57 2018 +0000

    Explicitly ensure when apt cache updates happen

    In https://review.openstack.org/547015 we adjusted
    the apt installation process to ensure that the cache
    update happens after the repository changes, but left
    out the explicit instruction not to do it in the task
    which changes the repo config.

    This patch adds that, but also seperates out the cache
    update into its own task so that the package install
    task remains more readable.

    Partial-Bug: #1750656
    Change-Id: Id70ad28caa63267c2bb17d8c56a8fa6e00cf55d4