Bug 750625 - Fix Coverity (11112) Uninitialized pointer read
    
    https://bugzilla.redhat.com/show_bug.cgi?id=750625
    
    plugins/replication/repl5_replica_config.c (replica_execute_ldif2cl_task)
    
    Bug Description: Using uninitialized "config.dir" when calling
    "cl5Open".
    config.dir is set in changelog5_extract_config.  If any error
    such as fail to read changelog config entry, NULL is set and
    following cl5Open fails.
    
    Fix Description: check if config.dir is NULL or not in error logging.