For Redis connections that operate over TLS, we need to ensure that we
are setting the correct arguments for the Redis client. We can utilise
the existing environment variable `DISCOURSE_REDIS_USE_SSL` to toggle
this behaviour.
No SSL verification is performed for two reasons:
- the Discourse application will perform a verification against any FQDN
as specified for the Redis host
- the healthcheck is run against the _resolved_ IP address for the Redis
hostname, and any SSL verification will always fail against a direct
IP address
If no SSL arguments are provided, the IP address is never cached against
the hostname as no healthy address is ever found in the HealthyCache.
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