Fix reload of retry_join server addresses on SIGHUP

[mlafeldt]

The current code does not update the actual config, but only the local reference to it.

/cc @denderello

[mlafeldt]

Speaking of config reloading, it looks like retry_join is the only setting currently updated by SIGHUP. Is this correct?

Also, I think it makes sense to implement the same logic for clients, so that they can be notified about new servers as well. What do you think?

[mlafeldt]

Regarding client retries: I checked the source code and reloading the list of servers via SIGHUP seems to be a bigger task since clients register with servers via RPC (buried deep down in the client code). Reloading is only really supported via Consul, it seems.

[diptanu]

Merging this change. Thanks! And yeah, it will probably need more work for the clients to refresh the list of servers via SIGHUP

[github-actions]

I'm going to lock this pull request because it has been closed for 120 days ⏳. This helps our maintainers find and focus on the active contributions.
If you have found a problem that seems related to this change, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.