maxscale not started with handle_server_events

Hi.

I tested the *handle_server_events *option, which has been supported since MariaDB 2.3.

[root@localhost local]# yum localinstall maxscale-2.3.15-1.centos.7.x86_64.rpm
Loaded plugins: fastestmirror
Examining maxscale-2.3.15-1.centos.7.x86_64.rpm: maxscale-2.3.15-1.x86_64
Marking maxscale-2.3.15-1.centos.7.x86_64.rpm to be installed
Resolving Dependencies
--> Running transaction check
---> Package maxscale.x86_64 0:2.3.15-1 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

====================================================================================
Package Arch Version Repository Size
====================================================================================
Installing:
maxscale x86_64 2.3.15-1 /maxscale-2.3.15-1.centos.7.x86_64 92 M

Transaction Summary
====================================================================================
Install 1 Package

Total size: 92 M
Installed size: 92 M
Is this ok [y/d/N]: y
Downloading packages:
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Installing : maxscale-2.3.15-1.x86_64 1/1
Verifying : maxscale-2.3.15-1.x86_64 1/1

Installed:
maxscale.x86_64 0:2.3.15-1

Complete!

[root@localhost local]# cat /etc/maxscale.cnf

...
[MariaDB-Monitor]
type=monitor
module=mariadbmon
servers=server1,server2
auto_failover = true
auto_rejoin = true
handle_server_events=on
...

[root@localhost local]# service maxscale start
Redirecting to /bin/systemctl start maxscale.service
Job for maxscale.service failed because the control process exited with error code. See "systemctl status maxscale.service" and "journalctl -xe" for details.

[root@localhost local]# tail -f /var/log/maxscale/maxscale.log
MariaDB MaxScale /var/log/maxscale/maxscale.log Wed Dec 11 15:30:38 2019
----------------------------------------------------------------------------
2019-12-11 15:30:38 notice : syslog logging is enabled.
2019-12-11 15:30:38 notice : maxlog logging is enabled.
2019-12-11 15:30:38 notice : Using up to 275.73MiB of memory for query classifier cache
2019-12-11 15:30:38 notice : Working directory: /var/log/maxscale
2019-12-11 15:30:38 notice : The collection of SQLite memory allocation statistics turned off.
2019-12-11 15:30:38 notice : Threading mode of SQLite set to Multi-thread.
2019-12-11 15:30:38 notice : MariaDB MaxScale 2.3.15 started (Commit: 216ce9b4ee18c3d77a555f3cacd45d20b4c94611)
2019-12-11 15:30:38 notice : MaxScale is running in process 17456
2019-12-11 15:30:38 notice : Configuration file: /etc/maxscale.cnf
2019-12-11 15:30:38 notice : Log directory: /var/log/maxscale
2019-12-11 15:30:38 notice : Data directory: /var/lib/maxscale
2019-12-11 15:30:38 notice : Module directory: /usr/lib64/maxscale
2019-12-11 15:30:38 notice : Service cache: /var/cache/maxscale
2019-12-11 15:30:38 notice : No query classifier specified, using default 'qc_sqlite'.
2019-12-11 15:30:38 notice : Loaded module qc_sqlite: V1.0.0 from /usr/lib64/maxscale/libqc_sqlite.so
2019-12-11 15:30:38 notice : Query classification results are cached and reused. Memory used per thread: 275.73MiB
2019-12-11 15:30:38 notice : Worker message queue size: 1.00MiB
2019-12-11 15:30:38 notice : The systemd watchdog is Enabled. Internal timeout = 30s
2019-12-11 15:30:38 notice : Loading /etc/maxscale.cnf.
2019-12-11 15:30:38 notice : /etc/maxscale.cnf.d does not exist, not reading.
2019-12-11 15:30:38 notice : Runtime configuration changes have been done to MaxScale. Loading persisted configuration files and applying them on top of the main configuration file. These changes can override the values of the main configuration file: To revert them, remove all the files in '/var/lib/maxscale/maxscale.cnf.d'.
2019-12-11 15:30:38 notice : Loading /var/lib/maxscale/maxscale.cnf.d/global-options.cnf.
2019-12-11 15:30:38 notice : Loaded module MariaDBBackend: V2.0.0 from /usr/lib64/maxscale/libmariadbbackend.so
2019-12-11 15:30:38 notice : Initialise readconnroute router module.
2019-12-11 15:30:38 notice : Loaded module readconnroute: V2.0.0 from /usr/lib64/maxscale/libreadconnroute.so
2019-12-11 15:30:38 notice : Loaded module MariaDBClient: V1.1.0 from /usr/lib64/maxscale/libmariadbclient.so
2019-12-11 15:30:38 notice : Initialise the MariaDB Monitor module.
2019-12-11 15:30:38 notice : Loaded module mariadbmon: V1.5.0 from /usr/lib64/maxscale/libmariadbmon.so
2019-12-11 15:30:38 error : Unknown parameter 'handle_server_events' for object 'MariaDB-Monitor' of type 'monitor'.
2019-12-11 15:30:38 warning: THE 'cli' MODULE AND 'maxadmin' ARE DEPRECATED: Use 'maxctrl' instead
2019-12-11 15:30:38 notice : Loaded module cli: V1.0.0 from /usr/lib64/maxscale/libcli.so
2019-12-11 15:30:38 notice : Loaded module maxscaled: V2.0.0 from /usr/lib64/maxscale/libmaxscaled.so
2019-12-11 15:30:38 warning: Persisted configuration files generated by runtime configuration changes were found at '/var/lib/maxscale/maxscale.cnf.d' and at least one configuration error was encountered. If the errors relate to any of the persisted configuration files, remove the offending files and restart MaxScale.
2019-12-11 15:30:38 error : Failed to open, read or process the MaxScale configuration file /etc/maxscale.cnf. Exiting.
2019-12-11 15:30:38 MariaDB MaxScale is shut down.
----------------------------------------------------

• Error: Failed to open, read or process the MaxScale configuration file. Exiting. See the error log for details.

The official MariaDB documentation is as follows:
https://mariadb.com/kb/en/mariadb-maxscale-23-mariadb-monitor/#handle_server_events

I checked it in 2.4.4, but the same result.