1. Binlog commit by rotate should not be used with
    Galera, so add an extra check during writing that
    the binlog is active (in case of WSREP binlog
    emulation).

 2. If the #binlog_cache_files directory exists on a
    mariadbd run without opt_log_bin, the directory
    was treated as a table/database, leading to errors.
    To fix, on startup, if opt_log_bin is disabled and
    #binlog_cache_files exists (in the default log
    directory), the directory is deleted.