freezer-api haproxy ssl config not being set

[Daniel Reader-Powell]

What happened:

When attempting to open the disaster recovery options in horizon I receive a SSL verification error.

"Error: SSL exception connecting to https://int-cloud.sys.192.com:5000/v3/auth/tokens: HTTPSConnectionPool(host='int-cloud.sys.192.com', port=5000): Max retries exceeded with url: /v3/auth/tokens (Caused by SSLError(SSLError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:897)'),)) "

What I expected to happen:

I would be able to setup and schedule some backups. This was previously working with Wallaby, but this has broken following an update to Xena.

How to reproduce it:

This may be specific to our environment as we use freeIPA to supply certificates to our services and set the following vars:

```
etcd_enable_tls: no
kolla_enable_tls_internal: "yes"
kolla_enable_tls_external: yes
kolla_admin_openrc_cacert: "/etc/pki/tls/cert.pem"
openstack_cacert: /etc/pki/tls/certs/ca-bundle.crt
kolla_enable_tls_backend: "yes"
kolla_verify_tls_backend: "yes"
kolla_tls_backend_cert: "{{ kolla_certificates_dir }}/backend-cert.pem"
kolla_tls_backend_key: "{{ kolla_certificates_dir }}/backend-key.pem"
rabbitmq_enable_tls: "yes"
```

OS:
NAME="CentOS Stream"
VERSION="8"

Kernel:
Linux controller01.sys.192.com 4.18.0-338.el8.x86_64 #1 SMP Fri Aug 27 17:32:14 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

Docker version: 20.10.14

Kolla Ansible Version: 13.0.1 (stable/xena)

Here's what I think is happening. The freezer_services defined as:
```
---
freezer_services:
  freezer-api:
    container_name: freezer_api
    group: freezer-api
    enabled: true
    image: "{{ freezer_api_image_full }}"
    volumes: "{{ freezer_api_default_volumes + freezer_api_extra_volumes }}"
    dimensions: "{{ freezer_api_dimensions }}"
    haproxy:
      freezer_api:
        enabled: "{{ enable_freezer }}"
        mode: "http"
        external: false
        port: "{{ freezer_api_port }}"
      freezer_api_external:
        enabled: "{{ enable_freezer }}"
        mode: "http"
        external: true
        port: "{{ freezer_api_port }}"
  freezer-scheduler:
    container_name: freezer_scheduler
    group: freezer-scheduler
    enabled: true
    image: "{{ freezer_scheduler_image_full }}"
    volumes: "{{ freezer_scheduler_default_volumes + freezer_scheduler_extra_volumes }}"
    dimensions: "{{ freezer_scheduler_dimensions }}"
```

Are missing the tls_backend variable. If I look at another service (heat in this example) I can see that the tls_backend variable is set like so:
```
    haproxy:
      heat_api:
        enabled: "{{ enable_heat }}"
        mode: "http"
        external: false
        port: "{{ heat_api_port }}"
        listen_port: "{{ heat_api_listen_port }}"
        tls_backend: "{{ heat_enable_tls_backend }}"
```

This translates to the haproxy service config as:
```
backend heat_api_back
    mode http
    server controller01 10.xxx.xxx.xxx:8004 check check-ssl inter 2000 rise 2 fall 5 ssl verify required ca-file ca-bundle.trust.crt
    server controller02 10..xxx.xxx.xxx:8004 check check-ssl inter 2000 rise 2 fall 5 ssl verify required ca-file ca-bundle.trust.crt
    server controller03 10..xxx.xxx.xxx:8004 check check-ssl inter 2000 rise 2 fall 5 ssl verify required ca-file ca-bundle.trust.crt
```

But the freezer-api is set as:
```
backend freezer_api_back
    mode http
    server controller01 10..xxx.xxx.xxx:9190 check inter 2000 rise 2 fall 5
    server controller02 10..xxx.xxx.xxx:9190 check inter 2000 rise 2 fall 5
    server controller03 10..xxx.xxx.xxx:9190 check inter 2000 rise 2 fall 5
```

I also note that the freezer-scheduler config is missing the os_ca_cert variable. e.g.
```
os_cacert=/etc/pki/tls/certs/ca-bundle.crt
```