fix lint error in travis-ci

[mmchen]

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[kirg]

@mmchen, i think lint is still throwing an error:

./services/outputhost/kafkaStream.go:46:2: don't use leading k in Go names; struct field kConverter should be converter
./services/outputhost/kafkaStream.go:51:1: comment on exported type KafkaMessageConverterConfig should be of the form "KafkaMessageConverterConfig ..." (with optional leading article)

[coveralls]

Changes Unknown when pulling 3baa5a8 on mingmin/fix-lint into ** on master**.