fix reload server method

[pete911]

Description of the issue

Describe the problem or feature in addition to a link to the issues.

Description of changes

server.Close only closes connections and does not wait for server shutdown. We can see this behaviour in the logs:

failed to serve and listen","error":"listen tcp :4311: bind: address already in use
failed to serve and listen","error":"http: Server closed"
failed to serve and listen","error":"http: Server closed"
failed to serve and listen","error":"http: Server closed"

http: Server closed error is coming from ListenAndServeTLS (s.shuttingDown() check, this means that the server is not shut down. After multiple tries, we get error from net.Listen. By using Shutdown(...) instead of Close(), the code is going to wait for server shutdown, not just for connections to be closed.

License

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Tests

Existing tests were re-run and are working. This change does not introduce any new behaviour.

Requirements

Before commiting your code, please do the following steps.

1. Run make fmt and make fmt-sh
2. Run make lint

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Integration Tests

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