fix result of a Grafana export bug
fix result of a Grafana export bug

see https://github.com/grafana/grafana/issues/6189

raintank/metrictank,raintank/metrictank,raintank/raintank-metric,replay/metrictank,raintank/metrictank,replay/metrictank,raintank/raintank-metric,replay/metrictank,raintank/raintank-metric,raintank/metrictank,replay/metrictank