fix windows tests (#421)
fix windows tests (#421)

Signed-off-by: Krasi Georgiev <92e9bca555ae3f6bf713b708c97f3f6dcff65542@redhat.com>
GoogleCloudPlatform/prometheus,Gouthamve/tsdb,alileza/prometheus,keegancsmith/prometheus,alileza/prometheus,kangwoo/prometheus,prometheus/prometheus,keegancsmith/prometheus,GoogleCloudPlatform/prometheus,prometheus/tsdb,prometheus/prometheus,alileza/prometheus,Gouthamve/prometheus,alileza/prometheus,Gouthamve/prometheus,keegancsmith/prometheus,prometheus/prometheus,kangwoo/prometheus,keegancsmith/prometheus,GoogleCloudPlatform/prometheus,alileza/prometheus,prometheus/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,keegancsmith/prometheus,Gouthamve/prometheus,kangwoo/prometheus,GoogleCloudPlatform/prometheus,kangwoo/prometheus,Gouthamve/prometheus