At startup, server loads configuration files.
However ConfigReloader does not know about already loaded files (files
is empty()), hence it will always reload the configuration just after
server starts (+ 2 seconds, reload timeout).
And on configuration reload the clusters will be re-created, so some
internal stuff will be reseted:
- error_count
- last_used (round_robing)
And if the reload will happen during round_robin test it will start
querying from the beginning, so let's issue config reload just after
start to avoid reload in the middle of the test execution.