Comment 2 for bug 1952414

this is not looking right, I'm troubleshooting a ci job failure https://openstack-ci-reports.ubuntu.com/artifacts/5d4/819438/2/check/bionic-ussuri-ha-ovn/5d44828/

```
2021-11-26 17:04:54.656762 | focal-medium | 2021-11-26 17:04:54 [INFO] Timed out waiting for 'neutron-api/0'. The workload status message is 'Services not running that should be: apache2' which is not one of '['ready', 'Ready', 'Unit is ready']'
```

```
neutron-api/0* blocked idle 4 172.16.0.254 9696/tcp Services not running that should be: apache2
```

Looking at it closer I found this:

In syslog:
```
Nov 26 16:38:34 juju-98a11d-zaza-4d85c92c4d57-4 systemd[1]: Starting The Apache HTTP Server...
Nov 26 16:38:34 juju-98a11d-zaza-4d85c92c4d57-4 apachectl[5947]: AH00526: Syntax error on line 13 of /etc/apache2/sites-enabled/openstack_https_frontend.conf:
Nov 26 16:38:34 juju-98a11d-zaza-4d85c92c4d57-4 apachectl[5947]: SSLCertificateFile: file '/etc/apache2/ssl/neutron/cert_172.16.0.254' does not exist or is empty
Nov 26 16:38:34 juju-98a11d-zaza-4d85c92c4d57-4 apachectl[5947]: Action 'start' failed.
Nov 26 16:38:34 juju-98a11d-zaza-4d85c92c4d57-4 apachectl[5947]: The Apache error log may have more information.
Nov 26 16:38:34 juju-98a11d-zaza-4d85c92c4d57-4 systemd[1]: apache2.service: Control process exited, code=exited status=1
Nov 26 16:38:34 juju-98a11d-zaza-4d85c92c4d57-4 systemd[1]: apache2.service: Failed with result 'exit-code'.
Nov 26 16:38:34 juju-98a11d-zaza-4d85c92c4d57-4 systemd[1]: Failed to start The Apache HTTP Server.
```

Then in the apache config `/etc/apache2/sites-enabled/openstack_https_frontend.conf`:
```
    SSLCertificateFile /etc/apache2/ssl/neutron/cert_172.16.0.254
    # See LP 1484489 - this is to support <= 2.4.7 and >= 2.4.8
    SSLCertificateChainFile /etc/apache2/ssl/neutron/cert_172.16.0.254
    SSLCertificateKeyFile /etc/apache2/ssl/neutron/key_172.16.0.254
```

Then in `/var/log/juju/unit-neutron-api-0.log`:

```
2021-11-26 15:56:29 DEBUG juju-log certificates:41: Writing file /usr/local/share/ca-certificates/vault_juju_ca_cert.crt root:root 444
2021-11-26 15:56:29 DEBUG certificates-relation-changed Clearing symlinks in /etc/ssl/certs...
2021-11-26 15:56:29 DEBUG certificates-relation-changed done.
2021-11-26 15:56:29 DEBUG certificates-relation-changed Updating certificates in /etc/ssl/certs...
2021-11-26 15:56:30 DEBUG certificates-relation-changed 129 added, 0 removed; done.
2021-11-26 15:56:30 DEBUG certificates-relation-changed Running hooks in /etc/ca-certificates/update.d...
2021-11-26 15:56:30 DEBUG certificates-relation-changed done.
2021-11-26 15:56:30 DEBUG jujuc server.go:211 running hook tool "juju-log" for neutron-api/0-certificates-relation-changed-4815572091935494528
2021-11-26 15:56:30 DEBUG juju-log certificates:41: Writing file /etc/apache2/ssl/neutron/cert_host-172-16-0-254.project.serverstack root:root 640
2021-11-26 15:56:31 DEBUG jujuc server.go:211 running hook tool "juju-log" for neutron-api/0-certificates-relation-changed-4815572091935494528
2021-11-26 15:56:31 DEBUG juju-log certificates:41: Writing file /etc/apache2/ssl/neutron/key_host-172-16-0-254.project.serverstack root:root 640
```

the charm is using `cert_${REVERSE_HOST}` instead of `cert_${IP_ADDRESS}`