Slave should reconnect less quickly when being disconnected due to duplicate server id

With MDEV-11177 being fixed we are now getting duplicate server IDs reported properly in the slaves error log.

Affected slaves will still try to reconnect immediately though, so flooding their error log with several log lines per second.

As it's clear that a duplicate server id requires a configuration fix that wouldn't happen within a fraction of a second slaves should throttle their reconnect attempts to one per second max., maybe even less.