Supplying a base64 encoded cert via ssl_ca breaks

[Liam Young]

The config.yaml says that ssl_ca should be base64 encoded but when the charm sets the sll_ca down its relation it base64 encoded the supplied option which means the clients get a double encoding

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/611125

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/611125
Committed: https://git.openstack.org/cgit/openstack/charm-rabbitmq-server/commit/?id=9ccf6d2b9535751ae3f586a771635347a9717049
Submitter: Zuul
Branch: master

commit 9ccf6d2b9535751ae3f586a771635347a9717049
Author: Liam Young <email address hidden>
Date: Tue Oct 16 18:33:48 2018 +0000

    Only b64encode ssl_ca if it needs it

    The description of the ssl_ca config option in config.yaml states
    that the certificate should be base64 encoded. But if it is then
    the charm b64encodes it again when sending the ca down the client
    relations. This change gates encoding the ca on whether it is
    already encoded.

    Change-Id: I9828d7567fd7f04cd0d80229ea1ff1275ea4269e
    Closes-Bug: #1798066