Remove outdated fluent-plugin-redis-counter
Remove outdated fluent-plugin-redis-counter

This plugin supports Fluentd v0.10.x.

Signed-off-by: Kenji Okimoto <7a4b90a0a1e6fc688adec907898b6822ce215e6c@clear-code.com>

fluent/fluentd-ui,fluent/fluentd-ui,fluent/fluentd-ui