MFH: r398676

sysutils/logstash: update 1.5.3 -> 1.5.4

Changes: https://github.com/elastic/logstash/compare/v1.5.3...v1.5.4

PR: 203539
Submitted by: Enrico M. Crisostomo <enrico.m.crisostomo@gmail.com> (maintainer)
Approved by: portmgr (erwin)