port series upgrade hook fails if unit is paused

[Liam Young]

Following the series upgrade guide *1 results in post-series-upgrade hook failure because the unit is paused.

The upgrade guide recommend pausing the non-leader units. When the series upgrade of these units completes it tries to start all the services but they are masked from the earlier pause so it fails. In addition it tries to start haproxy even if the charm is related to hacluster which means it should not be managing haproxy stopping and starting

*1 https://docs.openstack.org/project-deploy-guide/charm-deployment-guide/latest/app-series-upgrade.html#overview

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/705396
Committed: https://git.openstack.org/cgit/openstack/charm-swift-proxy/commit/?id=bbc0e3dcd31cf7df9c28981578f565b46da2ca61
Submitter: Zuul
Branch: master

commit bbc0e3dcd31cf7df9c28981578f565b46da2ca61
Author: Liam Young <email address hidden>
Date: Mon Feb 3 09:25:58 2020 +0000

    Unmask services during post-series-upgrade

    If a unit is paused then its services will not start during the
    post-series-upgrade hook. In addition exclude haproxy from the list
    of services to start if it is being managed by hacluster.

    Closes-Bug: #1861660
    Change-Id: I5f72f5507b9ed40b50dcacd1940e91d3cff26298