Fix for kafka logger (elastic#6430)

* Fix for kafka logger

The arguments are passed as slice (v) instead of a argument list (v...) which results in a wrong output in the log

* Add pull request to CHANGELOG

CHANGELOG.asciidoc

@@ -306,6 +306,21 @@ https://github.com/elastic/beats/compare/v6.0.1...v6.1.0[View commits]
 - Fix logstash output debug message. {pull}5799{5799]
 - Fix isolation of modules when merging local and global field settings. {issue}5795[5795]
 - Report ephemeral ID and uptime in monitoring events on all platforms {pull}6501[6501]
+- Fix panic when Events containing a float32 value are normalized. {pull}6129[6129]
+- Fix `setup.dashboards.always_kibana` when using Kibana 5.6. {issue}6090[6090]
+- Update Golang 1.9.4 {pull}6326[6326]
+- Fix conditions checking on autodiscover Docker labels. {pull}6412[6412]
+- Fix for kafka logger. {pull}6430[6430]
+
+*Auditbeat*
+
+- Add an error check to the file integrity scanner to prevent a panic when
+  there is an error reading file info via lstat. {issue}6005[6005]
+- Fixed an issue where the proctitle value was being truncated.
+- Fixed an issue where values were incorrectly interpretted as hex data.
+- Fixed parsing of the `key` value when multiple keys are present.
+- Fix possible resource leak if file_integrity module is used with config
+  reloading on Windows or Linux. {pull}6198[6198]
 
 *Filebeat*
 

libbeat/outputs/kafka/log.go

@@ -9,11 +9,11 @@ import (
 type kafkaLogger struct{}
 
 func (kl kafkaLogger) Print(v ...interface{}) {
-	kl.Log("kafka message: %v", v)
+	kl.Log("kafka message: %v", v...)
 }
 
 func (kl kafkaLogger) Printf(format string, v ...interface{}) {
-	kl.Log(format, v)
+	kl.Log(format, v...)
 }
 
 func (kl kafkaLogger) Println(v ...interface{}) {
@@ -31,8 +31,8 @@ func (kafkaLogger) Log(format string, v ...interface{}) {
 		}
 	}
 	if warn {
-		logp.Warn(format, v)
+		logp.Warn(format, v...)
 	} else {
-		logp.Info(format, v)
+		logp.Info(format, v...)
 	}
 }