fluent/fluentd — pull request #126 by tagomoris (2013-04-30 07:17:24+00:00)
Title: fix to suppress exception for flushing without any valid data

Fluentd configured with 'flush_interval' logs errors like below, with short downtime of forwarded node.
```
temporarily failed to flush the buffer, next retry will be at 2013-04-30 15:56:14 +0900.: no nodes are available
```

This log should be suppressed when buffer chunk is blank. So I wrote this patch.