Prometheus from master doesn't work with chronos exporter

[bobrik]

Not sure if it's still alive, but it doesn't work with prometheus from master:

# github.com/gettyimages/chronos_exporter
src/github.com/gettyimages/chronos_exporter/exporter.go:145: counter.With(e.mapper.labels(metric)).Set undefined (type prometheus.Counter has no field or method Set)
src/github.com/gettyimages/chronos_exporter/exporter.go:169: gauge.With(e.mapper.labels(metric)).Set undefined (type prometheus.Counter has no field or method Set)
src/github.com/gettyimages/chronos_exporter/exporter.go:196: counter.WithLabelValues().Set undefined (type prometheus.Counter has no field or method Set)
src/github.com/gettyimages/chronos_exporter/exporter.go:229: counter.With(e.mapper.labels(metric)).Set undefined (type prometheus.Counter has no field or method Set)
src/github.com/gettyimages/chronos_exporter/exporter.go:284: counter.WithLabelValues().Set undefined (type prometheus.Counter has no field or method Set)

Same as https://github.com/crobox/elasticsearch_exporter/issues/5