INT-3576: Fix NPE in the `RedisAvailableTests`

JIRA: https://jira.spring.io/browse/INT-3576
INT-3450 Support RFC 5424/6587 for SYSLOG

JIRA: https://jira.spring.io/browse/INT-3450

Use LinkedHashMap

- natural iteration order
INT-3450 Polishing - PR Comments