Steps to reproduce:

1. Add Plugins.Redis.Sessions.Redis.Password=<redis password>
2. redis-cli can return data for info and config section.
   redis-cli -p 6379 -a 'password' info
   ...
3. Replication
   role:slave
   master_host:0
   master_port:0
   master_link_status:down
   ...
4. Zabbix-agent2 with redis plugin return error.
   zabbix_agent2 -t redis.info[Redis]
   redis.info[Redis] [m|ZBX_NOTSUPPORTED] [Connection failed: MASTERDOWN Link with MASTER is down and slave-serve-stale-data is set to 'no'.]

Expected:
Ability to monitor redis hosts with any role.