Fix `make bench` (#610)
Fix `make bench` (#610)

Remove  flag -log.level
Signed-off-by: mrasu <457a8f485f40652b974da2b278af43cd01c8bce8@gmail.com>
GoogleCloudPlatform/prometheus,Gouthamve/prometheus,alileza/prometheus,keegancsmith/prometheus,GoogleCloudPlatform/prometheus,keegancsmith/prometheus,prometheus/prometheus,prometheus/tsdb,Gouthamve/prometheus,prometheus/prometheus,keegancsmith/prometheus,kangwoo/prometheus,prometheus/prometheus,alileza/prometheus,kangwoo/prometheus,prometheus/prometheus,prometheus/prometheus,alileza/prometheus,keegancsmith/prometheus,GoogleCloudPlatform/prometheus,alileza/prometheus,alileza/prometheus,kangwoo/prometheus,Gouthamve/prometheus,GoogleCloudPlatform/prometheus,Gouthamve/prometheus,GoogleCloudPlatform/prometheus,keegancsmith/prometheus,kangwoo/prometheus