MXS-3149 Properly remove master-status from server during demotion

Removing it from the pending status field has not effect as the
pending changes have all ready been written to real status.

server/modules/monitor/mariadbmon/mariadbmon.cc

@@ -514,8 +514,6 @@ void MariaDBMonitor::tick()
     }
 
     log_master_changes();
-
-    flush_server_status();
     process_state_changes();
     hangup_failed_servers();
     store_server_journal(m_master ? m_master->m_server_base : nullptr);