sysutils/rubygerm-fluentd: Update to 1.19.0

Release notes: https://github.com/fluent/fluentd/releases/tag/v1.19.0

Actively ignore upstream hack to avoid performance problems with Windows
as discussed in https://github.com/fluent/fluentd/issues/5041. FreeBSD
ports framework has no easy way to force old versions of rubygems, and
it seems that in this case it is also not relevant.