Correct return code for clickhouse-server init script

Why it matters

This change ensures that the clickhouse-server init script returns the proper exit status code. This improvement helps system administrators and automation tools accurately detect whether the server startup or shutdown was successful, preventing false-positive indications of success or failure.

How to use it

The fix is applied automatically with the updated version of the clickhouse-server package. Users do not need to perform any manual configuration; simply update to the version that includes this patch.