dc719ea Ticket 49696: replicated operations should be serialized

Authored and Committed by lkrispen a year ago
        Ticket 49696: replicated operations should be serialized
    
        Bug: there was a scenario where two threads could process replication operations in parallel.
             The reason was that for a new repl start request the repl conn flag is not set and the
             connection is made readable.
             When the start repl op is finished, the flagi set, but in a small window the supplier could
             already have sent updates and more_data would trigger this thread also to continue to process
             repl operations.
    
        Fix: In the situation where a thread successfully processed a start repl request and just set the repl_conn
             flag  do not use more_data.
    
        Reviewed by: Thierry, thanks