Comment 7 for bug 1929054

Reviewed: https://review.opendev.org/c/openstack/charms.ceph/+/792881
Committed: https://opendev.org/openstack/charms.ceph/commit/d1515daf737ceaca8e544b15bdcee5c10f67888e
Submitter: "Zuul (22348)"
Branch: stable/21.04

commit d1515daf737ceaca8e544b15bdcee5c10f67888e
Author: Trent Lloyd <email address hidden>
Date: Thu May 20 11:47:43 2021 +0800

    filter_missing_packages expects a list, not string

    filter_missing_packages expects a list and not a single package name as
    a string. Pass the chrony package as a single item list to avoid it
    checking installation candiates for 'c', 'h', 'r', 'o', 'n' and 'y'

    This patch simplifies the function, which makes it a little easier to
    reason about. Also a test is added to stop regressions in the future.

    [1] Ie3c9c5899c1d46edd21c32868938d3290db321e7
    [2] Ifef76eacd8bd837d2181ec75e406aa35f88b8b5b
    Closes-Bug: #1929054

    Change-Id: I93f53274bc8c7e62ebb8cb7bf81ff816f4bfd98b