Bind mount needed cert for haproxy for HA too

Bind mount needed cert for haproxy for HA too

haproxy needs the deployed SSL cert file to function when TLS is
enabled.

It is also required for the docker-puppet haproxy container since the
haproxy puppet module uses a validate_cmd to check the generated config
file is valid that fails when the required SSL cert is not present.
There is no clean way to disable this feature [1] so we need to bind
mount the cert into the container.

This commit applies the same change that was applied in
Id2df144b678769def204961236624091d4e5c457 for the non-ha case.

[1] https://github.com/puppetlabs/puppetlabs-haproxy/blob/4753ea5b2506ee093e9b4c8af6e91201d476d426/manifests/config.pp#L53-L57

Change-Id: I93e1ee86197bcf271f18a62a27c2f350ed3966ea
Co-Authored-By: Damien Ciabrini <dciabrin@redhat.com>