Using unique option prefix 'ignore_db_dir' is error-prone

see the following message in mysqld.log file:

2016-06-30 17:41:37 140391378425696 [Note] Using unique option prefix 'ignore_db_dir' is error-prone and can break in the future. Please use the full name 'ignore_db_dirs' instead.

when replaced 'ignore_dir_db' in my my.cnf file and restart the DB, the warning message went away. But according to the documentation:

--ignore-db-dir
Commandline: --ignore-db-dir=name
Description: Tells the server that this directory can never be a database. That means two things - firstly it is ignored by the SHOW DATABASES command and INFORMATION_SCHEMA tables. And secondly, USE, CREATE DATABASE and SELECT statements will return an error if the database from the ignored list specified. Use this option several times if you need to ignore more than one directory. To make the list empty set the void value to the option as --ignore-db-dir=. Corresponding read-only variable ignore_db_dirs shows the current list.
Introduced: MariaDB 5.3.9

ignore_db_dirs
Description: Comma-delimited list of directories in the data directory that are not considered as database directories. Set from --ignore-db-dir at startup.
Scope: Global
Dynamic: No
Data Type: string
Introduced: MariaDB 5.5

So am I supposed to replace 'ignore_db_dir' with 'ignore_db_dirs' or should I just ignore the warning in the mysqld.log file?

Thanks,
Chunli