With only one log-file no arguments are needed. The maxadmin command
'flush log' still accepts all the previous arguments, but warns about
them being deprecated.
Maxinfo now supports the shutdown command which shuts down a service, monitor
or MaxScale itself and the restart command which restarts a stopped monitor
or service.
The log manager variables lm_enabled_log_files_bitmask, log_ses_count
and tls_log_info that earlier were declared separately in every
c-file are now declared in the log_manager.h header.
